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Hollow Moon Magic: Altered Spells

by Sharon Dornhoff

Besides forbidding certain categories of spells outright, the Hollow Moon's patron Immortals also took steps to minimise the effects which other, permissible types of magic might have on lunar creatures and cultures. These changes apply to any spell which is cast in the HM setting, regardless of whether or not the caster is a Materan. Mystarans who travel to the Hollow Moon will have to discover how their magic has changed, by trial and error; likewise, a Materan-born spellcaster who leaves that setting's confines will soon discover that several of his or her spells work differently, beyond the effect of the Spell of Remembrance. Immortal magic is uninhibited by these effects, although Immortals can choose to allow the SoRs modifications when these changes are appropriate to the setting (as with light/colour effects) or actually increase spells' effectiveness (as with invisibility).

The three key concerns which guided the Immortals, in designing these alterations to mortal magic, were to ensure that lunar cultures remained free from outside/diurnal influences; to prevent future large-scale exterminations, such as the Saurolunarian Conflict; and to protect Matera's dark-loving races from the blinding "side effects" of spells which produce light, fire or lightning. All four HM Immortals supported these objectives, and mutual cooperation in planning the SoR allowed them to achieve their aims. Lesser goals, added on by individual members of the team, weren't 100% successful -- as when Ka fiddled with ESP-spells, in hopes of offsetting the mental block Demogorgon's artifact had inflicted upon the pteryx -- but they also influence how HM magics operate.

Altered Spells

Spells of Earthly Summoning -- The Hollow Moon, unlike the HW, doesn't have a blanket prohibition on summoning/conjuring magics. Only extraplanar beings and bodiless constructs such as Unseen Servants are a no-no; magics that bring creatures to serve from elsewhere in the Prime Material Plane, or which create Prime Material creatures, are perfectly acceptable. However, none of these spells can summon/create monsters or animals, which would have to brought in from outside the HM, itself: summoning spells can't pierce the lunar bedrock, nor can monster-creating spells create a species that's not native to the setting. The spells DO function, but everything they create or summon will be a natural inhabitant of the lunar environment (the result, if non-random, will be the nearest lunar equivalent to what the caster requested). For instance, an AD&D Mount spell could summon up saddle-trained footpad lizards or dire wolves, but not (diurnal) horses; an OD&D Insect Plague would function normally ... but the lunar insects it summons may glow in the dark! Consult the post on Hollow Moon wildlife, for a run-down on the types of animals such spells might summon/create, and assume that only nocturnal or crepuscular (dusk/dawn active) monsters from the Prime Material Plane can be called up by spellcasters.

Although summoning magics often bring unexpected results, when cast by Mystarans, DMs should take care not to give away important secrets with them. Having one of these spells summon a kopru to serve the PCs, before they've had a chance to solve the riddle of the koprus' mind-controlled empire, could spoil the suspense for everyone!

*** OD&D cleric spells : Insect Plague, Create Normal Animals
*** OD&D druid spells : Summon Animals, Creeping Doom
*** OD&D magical spells : Create Normal Monsters, Create Magical Monsters, Create Any Monster
*** AD&D priest spells : Messenger, Summon Insects, Animal Summoning I-III, Call Woodland Beings, Conjure Animals, Creeping Doom
*** AD&D wizard spells : Find Familiar, Mount, Summon Swarm, Monster Summoning I-VII, Conjure Animals
*** Gazetteer spells : Watcher (elf or shadow elf spell; Gaz5, Gaz13); Summon Herd (shaman spell, Gaz12); Summon Underground Animals (shadow elf spell, Gaz13); Call Totem (Gaz14)
*** GKoM spells : N/A

For the AD&D spell Call Woodland Beings, disallowed creatures include centaurs, dryads, satyrs and treants. Other faerie folk native to the moon might be available, if the DM wishes to design some. There ARE shadows in the HM setting, so Summon Shadow works normally; as for the availability of other undead, there's a post coming up about them, too.

Spells of Mass Destruction -- Mystara's first large-scale war, between the pteryx and Greater Carnifex, saw both sides develop spells and magical items of terrifying power; and the Hollow Moon's pteryx also drew upon this arsenal in their efforts to cull the "dangerous animals" -- i.e. the Ur-Carnifex tribes -- with which they shared Matera's interior. Fearing the pteryx might turn these same mass-destruction magics against the various other races which were arriving in the HM setting (as flyers, the pterosauroids could potentially launch attacks anywhere in the Nearside), the Immortals incorporated effects into the Spell of Remembrance that rendered the pteryx's most devastating spells impotent. In negating these super-magics -- most of which would be considered 11th level or higher spells, by contemporary standards; back in the M-Cretaceous, Mystara's magical energy was easier to come by -- the four HM patrons also "toned down" a great number of lesser area-effect combat spells ... especially, those of fire and lightning. The latter spells were singled out for extra restraints, because their light-shedding properties made them particularly hazardous to glare-sensitive lunar life forms; moreover, ALL the "heavy damage" attack-spells suffer a loss in area of effect, thanks to this stricture.

The first alteration -- applicable to all attack-spells which 1) have a pre-set area of effect; 2) inflict damage to hit points, rather than incapacitating without harm; and 3) invoke raw elemental forces (fire, lightning, frost, steam, gases, acid, etc.) when cast -- is that the areas of such spells' effects are reduced by 50% in every dimension. A Fireball cast in the Hollow Moon would encompass a sphere only 10' in diameter, while an AD&D Lightning Bolt would be half as long and wide as normal for whichever AoE the caster chooses: either 5' x 20' for a "forked" bolt, or 2.5' x 40' for a single one. Spells which target individual creatures, such as Melf's Minute Meteors, aren't diminished in AoE by this stricture, nor are "Wall"-type spells that create stationary obstacles of elemental energy. When in doubt, assume that any area-affecting spell of the "save-for-half-damage" type is subject to this reduction. Casters will easily see that their spells are reduced in area, when they start using magic in the Hollow Moon ... although they might only discover this fact, when the spell they just cast at a charging mob of opponents fails to take out more than a handful! ;-D

The second alteration -- imposed upon spells which employ fire (not just heat) or lightning (not just electricity) to inflict damage -- is that the damage dice for such spells are always reduced by one "step" in their magnitude: d6s become d4s, d10s become d8s, etc. The actual number of dice rolled remains the same, as do any bonuses added to the final result. A Delayed Blast Fireball cast by a 16th level OD&D magic-user would inflict 16d4 hp of damage; the same spell from an AD&D wizard does 10d4+10 hp*. For those spells in which damage is rolled on d4s, use d3s; for d3s, use d2s; d2s' spells inflict just 1 hp of damage per die. Spells (such as Explosive Cloud) which inflict a set number of hp damage per round, with no dice rolls needed, are unhampered by this stricture. Note that individually-targeted or "Wall" spells which employ fire or lightning are ALSO subject to this limitation, even though they are exempt from the previous one. Spellcasters who are new to the HM setting can "feel", upon casting these kinds of spell, that something is suppressing their magic's strength**; however, DMs might want to roll damage for PCs' spells in secret, the better to keep players unsure just how severely their damage-dealing potential has been impaired.

(* - Since most people don't have this many d4s -- AND since reading those little pyramids is a pain in the rear :-) -- damage for such spells can be rolled on d6s, as usual; any 5s and 6s should be re-rolled until results come up which you can keep.)
(** - Of course, the first time they get a look at lunar fire- or lightning-spells' "special effects", castes will probably have worse worries on their minds than how little damage they're inflicting! See below. ;-D)

A list of spells that are affected only by the area-reducing stricture, includes:

*** OD&D cleric spells : N/A
*** OD&D druid spells : N/A
*** OD&D magical spells : Ice Storm (Wall Of Ice effect works normally), Cloudkill, Explosive Cloud
*** AD&D priest spells : N/A
*** AD&D wizard spells : Ice Storm, Cloudkill, Cone Of Cold, Death Fog, Otiluke's Freezing Sphere (only affects "Globe Of Cold" effect)
*** Gazetteer spells : N/A
*** GKoM spells : Spout Of Scalding Wrath

Spells affected by the area-reducing AND the damage-reducing strictures, include:

*** OD&D cleric spells : N/A
*** OD&D druid spells : Call Lightning
*** OD&D magical spells : Fireball, Lightning Bolt, Delayed Blast Fireball, Meteor Swarm
*** AD&D priest spells : Call Lightning, Flame Strike, Fire Storm
*** AD&D wizard spells : Flaming Sphere, Fireball, Lightning Bolt, Delayed Blast Fireball, Incendiary Cloud, Meteor Swarm
*** Gazetteer spells : Ball Lightning (merchant-prince spell, Gaz9)
*** GKoM spells : N/A

And as for spells which suffer only a reduction in their damage dice, this list includes:

*** OD&D cleric spells : N/A
*** OD&D druid spells : N/A
*** OD&D magical spells : Wall Of Fire
*** AD&D priest spells : Fire Trap, Flame Blade, Produce Flame, Glyph Of Warding (fire or lightning effects), Produce Fire, Wall Of Fire, Fire Seeds
*** AD&D wizard spells : Burning Hands, Explosive Runes, Flame Arrow, Melf's Minute Meteors, Fire Trap, Wall Of Fire, Chain Lightning
*** Gazetteer spells : Sword Of Fire (shaman spell, Gaz12), Firebow (Gaz14)
*** GKoM spells : N/A

Spells of Illumination -- This category overlaps with the previous one, somewhat: it's yet another way that spells of fire and lightning are altered by the Spell of Remembrance. Unlike the strictures on attack-spells, the alteration of magical light should have very little effect upon game mechanics; it's there to (literally! ;-D) provide "local colour" to the Hollow Moon setting, not to weaken or strengthen a category of magic. The Immortals implemented this change because it protects Matera's light-sensitive creatures from "collateral damage" to their eyesight, when spellcasters do battle in the presence of bystanders. It also prevents overuse of Continual Light spells by crepuscular races from rendering the Nearside uninhabitable to purely-nocturnal species, or vice versa, for pure-nocturnals' use of Continual Darkness.

For those spells which create light as their primary function (as opposed to incidental light, as from a lightning bolt), the Spell of Remembrance allows a flexibility unknown on Mystara. In addition to the white light typical of Mystara's Light spells, casters may opt to produce either a soft, silvery-blue light similar to the Firmament's glow, or a deep red light like smouldering embers. Both of these shed an illumination equal to twilight -- or skybright, as Materans would describe them -- for (demi)human eyes, and they both have additional benefits which adventurers could find surprisingly useful. The "bluelight" doesn't rob a person of their night-vision or infravision, as torchlight or daylight does, and if a stationary light of this colour is spotted from afar, observers might (Intelligence check) mistake it for a clump of glowing "litholichten" crystals. While "redlight" isn't as inconspicuous, it's got the advantage that most HM arthropods and mammals can't actually SEE light at the extreme red end of the spectrum*, so won't notice or be frightened away by it. Even the more dark-adapted of Matera's sentient races are redlight-blind, and can be fooled in this manner. Spellcasters from Mystara probably won't realise these colour-changes are an option, until they've seen lunar casters' spells in action, but once they learn that it's possible they are free to choose bluelight or redlight whenever they cast an illumination-spell. These spells can still be cast at their full "white light" brightness, if desired.

(* - This is why zoos' exhibits of nocturnal mammals routinely use red lighting: the animals can't see that wavelength of light, so remain awake and active in spite of it.)

A second, simpler change to spells of this category is that none are permanent. Continual Light/Darkness lasts for 1 month per caster level, in the Hollow Moon, and illumination- or darkness-spells cannot be made Permanent. Continual Light/Darkness spells which are brought in from outside the setting, already functional, fail when the 1 month/level duration runs out, or after 1d6 hours if they've already been in effect beyond that time-limit.

The last effect of this aspect of the SoR, upon light-generating magic -- and the one that, if done right, should shake up the nerves of your PLAYERS, as well as their characters! -- is that spells of fire and lightning don't just inflict less damage in the HM setting: they LOOK different, too. A LOT different. While mundane fires and natural lightning don't appear any different from similar phenomena on Mystara, magically-generated flames and bolts manifest in eerie, dim-lit forms which should seem downright creepy (!) to Mystaran PCs, the first few times they cast them in the moon. Rather that the usual red/orange/yellow blazes, HM fire-spells create "moonfire" -- wispy, pastel flames of blue, purple and green*, that crackle with sounds reminiscent of a hag's wicked cackling, and seem to flicker and dance in slow motion -- while lightning-spells call up "blood lightning": throbbing, crimson bolts that cut a jagged path of red to their destination, ripping their way through the air with the sound of (demi)human shrieks! From time to time, crazed faces seem to form in the surface of moonfire flames, sneering at and mocking observers; in the wake of a bolt of blood lightning, an iron-tainted scent of spilt blood lingers in the air, and the very ground seems to shudder in horror.

(* - Fires set alight by these spells burn with normal, orange flames. Moonfire isn't related to blackfire, the halfling clan relic, as it's hot and it burns the things you normally expect a fire to burn.)

DMs should play up the weird, UN-natural nature of these spells -- Go on, ham it up! Make those PCs' hair turn white! :-) -- to the hilt, whether they're being cast at the party, or BY the party. Mages can be led to think they've lost control of their powers, or that some evil force is twisting their magic; priests -- who can't Commune for advice, remember...? -- might well assume their Immortal patrons are furious with them, for some unknown, ghastly reason. In actual fact, it's all just smoke and mirrors: a special-effects display, courtesy of the Spell of Remembrance. Korotiku (everyone's favourite Immortal wise-guy) added these perceptual tricks on, as an afterthought -- and, let's face it, a bit of a jab at unsubtle spell-slingers -- to ensure that destructive fire- and lightning-spells wouldn't be used very often* by Materans. More importantly, "moonfire" isn't bright enough to pose a threat to lunar creatures' sensitive eyes, and blood lightning -- like redlight -- is all but invisible, to the most-vulnerable races' retinas. (That's the one reason the other three Immortals let him get away with this bit of morbid humour ... that, and Ordana's treantish belief that the only good fire-spell is the one that's never been cast.)

(* - It worked, too! Most Materans think of fire- and lightning-spells as "evil magic", in much the same way Mystarans think of necromancy. (A self-proclaimed "Follower of the Flame" can potentially get lynched, in jumpier regions.) Materan battle-magic typically draws on other elemental forces, such as lava, frost or steam, along with incapacitating effects like Web, and a wide range of sense-blinding -- for all kinds of senses -- effects.)

Spells that are affected by these tenets of the SoR include ALL of the spells from the previous category which are reduced in damage dice (i.e. all the fire- and lightning-spells above), plus:

*** OD&D cleric spells : Light, Continual Light/Darkness
*** OD&D druid spells : Produce Fire
*** OD&D magical spells : Light, Continual Light/Darkness
*** AD&D priest spells : Light, Continual Light/Darkness, Pyrotechnics (Fireworks effect), Starshine, Moonbeam, Sunray
*** AD&D wizard spells : Affect Normal Fires (flames become moonfire while spell operates), Dancing Lights, Light, Continual Light, Darkness 15' Radius, Pyrotechnics (Fireworks effect), Fire Charm (flames become moonfire while spell operates), Fire Shield
*** Gazetteer spells : Faerie Lights (elf or shadow elf spell, Gaz5 and Gaz13); Radiance (master spell, Gaz8)
*** GKoM spells : N/A

Faerie Fire is unaffected by any of these changes, except that it cannot be made permanent.

Spells of Charming -- In a straightforward attempt to curtail a type of magic her own free-swimming nature found abhorrent, Seshay-Selene tried to extend the SoRs magic-dampening effects to exclude charm-magics, just like the SoPs did. But as she hadn't taken part in creating the SoP and wasn't entirely sure how it worked, the Immortal whale slipped up: she succeeded only in reducing the range of HM charm spells, not in eliminating them entirely. (Hey, even Immortals can have their off days.... :-D) Spells of Charming and direct mind control always have a range of "Touch", in the Hollow Moon setting, regardless of their range in the outside world; any charms designed to work at a distance simply fail (see "Useless Spells", for a list of these). Would-be Charm casters must either employ these effects as a touch attack, in the manner of priests' reversed healing-spells, or must trick victims into letting the caster make physical contact. The Mass Charm spell has a duration of 1 turn, during which the caster possesses a "charming touch" useable on as many subjects as the spell's normal maximum number of targets. All other Charm spells allow their caster one round per spell-level to use them, before they expire. This stricture only affects spells which Charm in an invasive manner, suppressing the will or emotional and/or bodily control of their victims. It doesn't apply to subtle spells that enhance the caster's appeal (e.g. Friends, Fellowship, Saviour Faire) in the eyes of others, or captivate peoples' attentions with visual or verbal distractions (e.g. Hypnotic Pattern, Enthral, Leomund's Lamentable Belabourment) without conferring control over their actions.

Mystarans, of course, may assume these spells have no effect in the HM setting, if they aren't touching anyone the first time they try to cast a Charm there. Then again, they might happen to cast one when they're "aiming" at a distant target ... but touching a fellow PC!

*** OD&D cleric spells : Quest
*** OD&D druid spells : N/A
*** OD&D magical spells : Charm Person, Charm Monster, Geas, Charm Plant, Mass Charm
*** AD&D priest spells : Animal Friendship, Charm Person Or Mammal, Quest
*** AD&D wizard spells : Charm Person, Hypnotism (must touch subject while making Suggestion), Suggestion, Charm Monster, Emotion, Fire Charm (must touch subject while making Suggestion), Charm Plants, Mass Charm
*** Gazetteer spells : Charm Animal (dervish, wise woman, or merchant spell; Gaz2, Gaz7 and Gaz11); Animal Charm (shamani spell, Gaz14 -- shamani can Charm their totem animal without having to touch it)
*** GKoM spells : N/A

Note that some Charms (e.g. Soothe The Beast) already have a range of "Touch", working normally in the Hollow Moon. They aren't listed here. On Matera, practitioners of the Secret Craft of Witchcraft/Wokanism must touch a creature to put it under their influence, just like everybody else.

Spells of Mind Reading -- Another Immortal idea that didn't go entirely as planned, this HM stricture affects all spells of thought-based communication, ESP, and mind-to-mind contact other than Charms. Originally, Ka proposed this alteration to try and undo the damage Demogorgon had inflicted upon the world-view of the pteryx; unfortunately, it backfired, when a second race of mental prodigies -- the kopru -- were later introduced to the Hollow Moon.

Ka's idea was simple. If the pteryx couldn't accept that non-telepaths were sentient, then why not make all spells of mental contact (ESP, in OD&D games; various spells of Thought and Mentalism, in AD&D) work for two-way communication, not just one? Surely that'd let other races establish their credentials, as self-aware beings, upon encountering the pterosauroids! So that's what the SoR does: it allows any sentient creature on Matera, whose mind is being read by a spell, to instantly detect the caster's probing and to read the caster's thoughts, in turn. The targets of such spells may read their casters' minds under the exact same limitations -- concentration, time requirements, etc -- as vice versa. Alternately, either participant in a mental link -- caster or subject -- may opt to cut off communication at any time during the duration of contact, if he or she makes a successful save vs Spells (mental resistance bonuses for Wisdom apply, in AD&D games). Naturally, PCs may choose to drop a mental link in surprise, the instant they make contact, and pick up a train of thought like: "Whoa, there's somebody in my mind! And I sense that he's come a long, long way to get here... hey, he's a human, how about that...? Don't see them every day... and now he's getting spooked, because I can hear him...!" Attempts to probe a mind for specific information should be resolved as an opposed Intelligence check between the two mentally-linked individuals; whoever rolls the highest score on a d20, without exceeding his or her Int, wins the struggle*. Ties indicate that the information is not obtained.

(* - DMs can deliberately withhold information that would totally spoil an adventure, of course; still, some reward for effort is warranted. You should always give a PC who successfully probes a mind SOME information of value, but it needn't be what they were actually looking for.)

For a while, this two-way stricture on telepathy-magics was a success; pteryx recognition of the hsiao as sentient, for example, dates from the early days of the SoR and the use of these spells. But when the Dahyu-manah-bitu -- formidable kopru overlords from Davania's Vulcanian Peninsula, who'd systematically infiltrated many great nations of the Nithian era via their own mental prowess -- arrived in the setting, the downside to such bidirectional ESP-magics became clear ... for anyone who attempted mental contact with a kopru-controlled subject, immediately became susceptible to the influence of the slick-skinned Framatars ("Masters"), even beyond the normal range of kopru special attacks! Soon enough, the pteryx discovered the kopru's mental presence within the minds of other races ... whereupon, the pterosauroids concluded that ALL the "sentience" they'd briefly ascribed to speaking races had been kopru-induced. Worse yet, the Dahyu-manah-bitu quickly seized upon ESP spells as a means by which catspaw-mages -- Charmed by kopru natural abilities, with which the SoR does not interfere -- could move freely about the Nearside, unsuspected and unhindered by the dryskin-world, and bring more victims under their Framatars' sway. In game-terms, anyone who casts a spell of mental contact upon a kopru-Charmed subject or catspaw, or who is targeted with such a spell by a victim of kopru control, must save vs Death to resist kopru influence, exactly as if he or she were attacked with the mind-power of the Framatar in question. What Ka and the other Immortals had intended as a bridge between races, had become a weapon in the grasp of satraps of the kopru Dominarchy.

Spells that are subject to this stricture-gone-wrong are thankfully few. They include:

*** OD&D cleric spells : N/A
*** OD&D druid spells : N/A
*** OD&D magical spells : ESP, Clairvoyance*
*** AD&D priest spells : N/A (many ToM spells of the Thought sphere are affected)
*** AD&D wizard spells : ESP (many PO:S&M spells of the Mentalism school are also affected)
*** Gazetteer spells : N/A
*** GKoM spells : N/A

(* - The OD&D version of Clairvoyance sees through the eyes of another creature, whereas the AD&D version sees things from a selected location. Thus, only the former is affected by this stricture, such that the subject can see through the caster's eyes.)

Spells of Invisibility -- A simple change, this one was recommended by Ordana as the ancient protector of woodland races, some of whom depend on invisibility-magic to guard themselves from their enemies. (Note: This alteration, unlike all the other prohibitions and structures, applies both to mortal spells AND inborn monster abilities! Hence, even naturally-invisible creatures such as pixies have their powers modified by this aspect of the SoR.)

Because there are so many different races in the HM setting, few of whom depend entirely on vision (infra- or otherwise) to perceive their surroundings, standard Invisibility is of limited use for Materans. Therefore, the SoR makes this sub-set of illusions much more flexible: rather than always concealing a recipient from sight, they can conceal their subject from any ONE sensory mode of the caster's choice ... even from senses, such as cryions' echolocation or sharks' electrosensitivity, which the caster doesn't possess or comprehend! There's no need to specify which sense will be affected, until a lunar Invisibility spell is actually cast; at which point, the caster may freely choose to render the recipient(s) unseeable, inaudible, scentless, echo-invisible, electrically-inert, vibrationless, or whatever. Only the physical senses can be fooled, in this way; supernatural sensory abilities of monsters, such as certain undead beings' power to sense living presences, are not deceived.

An Invisibility-caster can either specify which sense the recipient is to be made undetectable to, by name, or he or she can choose the race from which the subject(s) should be concealed. In the latter case, the primary sense of the race in question is always the one that's foiled, even if the caster isn't sure which sense that particular race depends upon (if a race has two primary senses, select the blacked-out sense randomly). Multiple senses can be foiled with additional applications of Invisibility, up to a maximum of four different sensory modes.

In game terms, each race can be considered to have primary, secondary, and tertiary senses. Primary senses are the highly-developed ones on which a creature relies in routine activities, while secondary senses help support the primary sense(s) with their supplemental input, and tertiary senses are weak and not especially reliable. Concealment from an opponent's primary sense -- no matter what that sensory mode may be -- imposes the same combat penalties upon that opponent, as does Invisibility for primarily-sighted opponents (humans, demihumans, most humanoids). Thus, a race of blind monsters who rely upon hearing as their primary sense would attack inaudible foes with the exact same penalties as the core rules recommend for PCs vs. invisible ones. Opponents with only one secondary sense (hearing, for most of the PC races) get no bonuses for it, fighting "primary-sense-Invisible" foes.

If a combatant has two secondary senses, like the SC lupins and rakasta -- who are sighted as their sole primary sense, but can respectively boast keen olfactory or tactile (whiskers) secondary senses, as well as sharp hearing -- they are much less hobbled by the failure of their primary sensory mode. They are therefore considered to have the Blind-Fighting non-weapon proficiency (AD&D rules)*, or to take only half the usual penalty vs invisible opponents (OD&D rules), when fighting enemies that are Invisible to their primary sense. Races with multiple primary senses (keen-nosed AD&D dragons able to detect invisible creatures, for one) don't suffer any combat penalties, until ALL of their primary senses have been fooled by multiple Invisibility spells. The tertiary senses -- e.g. smell, touch and taste, for (demi)humans -- provide only minimal input, so can't do anything to offset Invisibility's combat penalties ... although they can certainly offer clues that a magically-concealed creature is nearby.

(* - The Red Steel rules already establish that these races are considered to have the Blind-Fighting proficiency. I'm simply expanding that precedent here, to cover other races and monsters with special/weird sensory abilities.)

Affected spells under this stricture:

*** OD&D cleric spells : N/A
*** OD&D druid spells : N/A
*** OD&D magical spells : Invisibility, Invisibility 10' Radius, Mass Invisibility
*** AD&D priest spells : N/A
*** AD&D wizard spells : Invisibility, Invisibility 10' Radius, Improved Invisibility, Mass Invisibility
*** Gazetteer spells : N/A
*** GKoM spells : N/A

Note that specialised AD&D priest spells, like Invisibility To Undead or Invisibility To Animals, and the Gaz12 shamans' spell Invisibility To Spirits, already cover all the senses of their intended subjects, so aren't altered by this stricture.

Spells of the Spectrum -- The last category of spells which should definitely be altered, in any HM campaign (the better not to "clash" with the setting! ;-D) are spells which manifest in the form of the colours of the rainbow, i.e. prismatic, chromatic, and other "colour-coded" spell effects. The traditional seven-colour rainbow doesn't exist, in the blue-lit Hollow Moon setting -- there's no red, orange or yellow bands, to HM rainbows or spectra -- and those spells which display themselves as "rainbow" patterns invariably conform to the altered colour-scheme of the Firmament's light.

In place of these first three colours of the 7-shade (red, orange, yellow, green, blue, indigo, purple) Mystaran spectrum, prismatic-type spells substitute pastel versions of the other shades. Materan "rainbows" consist of the following colours/tones: lavender, sky blue, pale green, grass green, deep blue, indigo, purple. Grass green, deep blue, indigo and purple respectively correspond to the green, blue, indigo and purple shades of the Mystaran spectrum; these retain their normal colours and functions, although they are of a darker shade than usual. The red bands/beams/etc of a spectrum-based Mystaran spell will appear lavender, in the Hollow Moon; the usually-orange ones manifest as sky blue; beams/layers/whatever that would look yellow on Mystara are pale green, in Matera-cast prismatic spells*. The order of appearance, effects, and other properties of these spells are not altered, in the slightest: the change is purely cosmetic. Thus, the sky blue (=orange) layer of an OD&D Prismatic Wall still blocks non-magical missiles, inflicts 24 hp damage, can be brought down by magical lightning and is the second layer of the Wall encountered by attackers. The pale green (=yellow) missile of an AD&D priest's Rainbow still does double damage to vegetable-based targets. The lavender (=red) version of Chromatic Orb still does ... whatever kind of damage that spell's red orb normally does. (I haven't got that book with me now! :-P) The coloration might've changed, but not the effect. Spells which display rainbow colours, without the various shades having unique individual effects -- e.g. Colour Spray -- are also made to match the lavender-sky blue-pale green-grass green-deep blue-indigo-purple colour scheme of lunar spectra, by the Spell of Remembrance.

(* - This only applies to spell-produced "rainbows". Natural meteorological rainbows and the spectra of prisms, generated from ambient lunar light -- rare, but they do occur -- are simply missing their red, orange and yellow components. (In effect, the "lavender-sky blue-pale green" portions of magic spectra, in the HM setting, are what a lunar DOUBLE rainbow looks like!) Just as a reminder, the Firmament's light makes red or orange things look black, yellow things look blue-green or grey-green, and white or grey things look pale blue. Brown colours will look either black or dirty olive, depending on whether they have a reddish tone under normal (white) light; tans look olive or aqua. If you'd like to seen this colour-shifting effect for yourself, go out and buy a $3.00 "party" light bulb -- deep blue or indigo in colour; C'mon, you've spent loads more than that, on all your other gaming junk! ;-D -- and take a look at objects of various colours under its light. (Some of the Gazetteers' full-colour cover art is ideal!) Be sure the bulb provides the ONLY light present when you do this, as even a tiny trace of non-blue illumination seeping in under a door can spoil the effect; a pitch-black closet or basement will probably be necessary.)

Spells which undergo this change in spectrum, in the Hollow Moon, include:

*** OD&D cleric spells : N/A
*** OD&D druid spells : N/A
*** OD&D magical spells : Prismatic Wall
*** AD&D priest spells : Rainbow
*** AD&D wizard spells : Colour Spray, Hypnotic Pattern, Rainbow Pattern, Prismatic Spray, Prismatic Wall, Prismatic Sphere
*** Gazetteer spells : N/A
*** GKoM spells : N/A

Miscellaneous Alternations to Spells: Day Length & Other Details

Simply because a "day", in the Hollow Moon setting, is a whopping 672 hours long, spells that have a duration of "one day" or "until midnight" require clarification. On or in Matera, all spells with a duration in days will operate for exactly 24 hours per "day" they'd normally last. Spells which expire at dawn, dusk, noon or other once-a-day occasions, on Mystara (e.g. the merchant-prince spell Nightwatch, from Gaz9), expire exactly 12 hours after they are cast.

Spells that can be cast only at night can be cast any time but skybright, while those which must be cast in the daytime will work at any time but fulldark. Spells that receive bonuses or are otherwise influenced by the moon being full (e.g. Summon Spirit, from the CBN), ALWAYS receive the benefits of being cast under a full moon, on Matera, as you'll never get a greater "lunar influence" upon your magic, than you get from actually being there.

If a spell requires moonlight to be present for it to function -- I'm not sure, but I THINK some FR spells from the WSpCmp have this requirement -- they'll work at any time of month/lunar "day" except for fulldark. Spells that only work in sunlight, such as various Al-Qadim spells which DMs may have made available to Ylari spellcasters, just plain won't function, in the Hollow Moon's eternal twilight (Sorry, True Believers! :-( ).

Material components and magic item construction-materials may be hard to come by, for spellcasting characters from Mystara, until they learn which lunar equivalents are available. Materan mages and priests (or aranea and hsiao, for the open-minded) can give newcomers pointers on the components they use themselves, although not for things like fire-spells which lunar spellcasters shun.

One of the Seven Secret Crafts of Glantri -- that of Alchemy -- has made its way into the Hollow Moon setting. There's a 5th circle Alchemist on Matera, so if the Glantrian High Master of Alchemy ever showed up on the moon, he (She...? Is Dame de Sephora a 5th Circle...?) would eventually have to fight over the position. OTOH, the relative rarity of humans in the Hollow Moon setting means that high-level druids are hard to come by; Mystaran druids will probably find vacancies there, although Matera does have a Great Druid. Mystics' ranks are fully occupied on Matera, thanks to Vedal's monasteries, and to the Nephthisian Exodus and its descendants.

The Hollow Moon -- for whatever reason -- is NOT subject to the effect of Mystara's Day of Dread. Indeed, even the "Week Of No Magic" passed it by (!), in 1009. Magic works fine, year-round, in the HM setting ... although it might fail (with fatal consequences) for those on the exterior of Matera.