The Black Mage – Selling Your Soul for Fun and Profit

Part of writing my game has been trying to make it setting neutral, so that (for example) races don't do anything, because a GM may want to make their elves the usual tree-huggers, or may want to make them flesh-eating cannibals or fey with a completely alien morality or whatever instead.  A ruleset where elves have a bonus to hide in forests or dwarves gain the ability to see in the dark and understand stonework creates an implied setting: mechanics that effectively state the way things are without spending a single word on setting / flavour text.  There's nothing wrong with that, but it's simply not what I'm after: I'm trying to make a neutral engine.

Along these lines, magic has a rather noticeable if underappreciated effect on your implied setting.  Beyond the obvious, which is that magic exists and so any number and type of amazing things can be dropped into a setting, many specific spells greatly shake up the world if taken at their word: Continual Light being perhaps the most obvious, but Animate Dead, Raise Dead, and Permanency being of especial note.

What I think is less considered here is the nature of magic itself.  The default magic system for D&D is Vancian casting.  I'm quite fond of it, and have no interest in the thousands of failed alternatives that have been proposed over the decades because it's "not realistic" or what have you.  However, Vancian casting as seen in D&D is a system with a decidedly academic basis.  That is, it all works off of spellbooks, which in turn requires literacy and the production of books and scrolls, and additional implied research and training.  As a system it's all very, well, systemic.

There's nothing wrong with that either, but strictly speaking in terms of implied settings, it does close off a lot of worldbuilding avenues unless one wants to lean heavily on clerical magic.  What if you want to have innate magic-users?  How do you handle arcane magic in non-literate societies?  What did arcane magic look like before the institutional framework was created that made the literate style possible?  And, most importantly, how do I sell my soul to the forces of evil in pursuit of quick and easy power?

The base concept is not new, of course.  Sword & sorcery fiction is full of this sort of thing (and DCC has built its magic system around things going terribly wrong as you wield its power).  D&D nods in this direction with the DMG's witch doctors, but on the whole it's lacking, and one of my goals is an attempt to expand on elements like this that traditional D&D tends to be weaker at.  Dissatisfied with the idea of sacrificing a virgin and summoning Baphomet in pursuit of terrible sorcery, only to told in a cavernous voice echoing with a thousand thousand screams, "there will be a test on Monday", and then handed a pile of books and ink quills, I decided to construct some alternate systems, not to replace Vancian casting, but to complement it.

Of course, you could always just take a conventional magic-user, add an evil alignment, a two-line backstory, and a roll or five on a random corruption/mutation table (I'm fond of the ones in The Metamorphica: Revised).  This is intended for those who want a more systemic approach to the subject, with results that can be gained through actual play.  I've looked to the influences given above, as well as the general sense of the Dark Side system in the old West End Games Star Wars RPG.

My GM's Manual has the write-up on this for my own system (it's there because I don't really expect it to be a typical player option, though it's possible), but here's a full D&D equivalent.  Non-evil versions I'll tackle another time.

BLACK MAGES

The fell powers that offer this path promise much, and indeed, such sorcery is tantalizingly easy to master.  However, all things have a price, and in time the caster is likely to find that such power ends up mastering them.

A black mage must be either Evil (any variant) or Chaotic (if using 3-axis alignment).  They use all Magic User level tables, spell tables, and save values.

Preparing Spells

Black mages must still memorize their spells as normal from a "spellbook", but instead of a tome this is some sort of easily recognizable fetish, always made of bone, that the mage will feverishly guard--the symbol of their link to the outer-planar force they made their bargain with (normal item saves apply to the fetish, but apply a +1 save bonus per Corruption level (see below) that the mage has.  For a black mage, spell memorization is performed as normal but is only a vehicle allowing their otherwise untrained minds to absorb the power lent to them without dissolving.

New spells are gained as normal when levels are gained, and by touching the fetish to a spellbook or another fetish and following the same process a normal magic-user would to learn a spell from it, spells can be taken from the spellbook and bound to the fetish.  The Chance to Know any given spell is based on Int as normal but is always at least 55%, +5% per Corruption level possessed.

Corruption

Black mages have a Corruption threshold, which is their Wisdom score plus their Intelligence modifier (if any).  Each time a black mage successfully casts a spell, they must roll a D20, adding a modifier equal to the spell’s level.  If the result is over their Corruption threshold, they gain a number of Corruption points equal to twice the spell’s level.  A roll of 20 is always a failure, and applies double the normal points amount.  (If the GM wishes to avoid these rolls, they can instead automatically apply the points each time, in which case the points should always be equal to the spell's level, rather than twice it.)

Whenever a black mage goes up a level, the GM rolls percentile (D100).  If the result is equal to or less than the character’s Corruption points total, they are marked by the powers they wield: reduce their Corruption points to zero, but apply 1 Corruption level.  If the result is over, there is no effect and the points continue accruing.  Alternately, instead of rolling, a black mage with at least 1 Corruption point can always choose to embrace the dark powers and automatically gain the Corruption level.

Aethelred decides that reading is hard and sells his soul to Juiblex for power.  He has a Wisdom of 8, befitting someone to whom this sounds like a good idea.  Moderately clever all the same, he has a +1 Intelligence modifier.  This gives him a Corruption threshold of (8+1) 9.  Each time he casts a spell, the player rolls a D20: on a 10 or higher (with a modifier applied equal to the spell's level) Aethelred gains Corruption points equal to twice the level of the spell just cast (e.g. for a Magic Missile, 2 points; for Power Word, Kill, 18 points).

A wielder of black magic does not just gain unearned power: they can dare to drink deep from the well of darkness and so wield even more magic than their more typical academic-bound cousins.  An experienced black mage can choose to prepare more spells than permitted by their level.  The maximum number of additional spell slots allowed at any given spell level is one for every two full Corruption levels, to a minimum of 0 and maximum of 6.  These extra slots can be applied as desired each time a mage prepares their spells, but cannot be applied in such a way that the bonus slots exceed the base number of slots of a given spell level.  Each additional spell slot so prepared that day gives the mage a number of Corruption points equal to that spell’s level.

As Aethelred grows more familiar with this wellspring of evil, over time his ability to draw on it grows.  At first he can't prepare anything extra: it's enough that he can wield power normally requiring several years of dedicated study despite being a lazy git.  But at Level 10 he could have up to 10 Corruption levels (depending how he rolled on his Corruption checks and whether or not he embraced the darkness along the way).  That's good for up to five free spell slots as desired each time he prepares his spells for the day.  However, he can only apply two of those free slots to his 4th or 5th-level spells, because at 10th level he only has two base spell slots at those levels.  Of course, at 10 Corruption levels he's also getting minimum results of 11 on the Corruption tables and average results of 17-18...

The Price

Each time a Corruption level is gained, the mage must roll once on each of the Physical and Spiritual Corruption Tables.  Add 1 to these rolls for each Corruption level the mage has; reroll duplicate results as well as contradictory ones (unless the result can conceivably repeat/stack).

 Physical Corruption Table

1D12 Result	Corruption
1	The mage can only eat raw meat
2	The mage’s eyes change to an unnatural colour
3	The mage’s pupils resemble that of a cat or serpent
4	The mage’s eyes become large and unblinking like a fish, or segmented like a fly
5	Small horns appear on the mage’s forehead. Multiple instances of this increase the size of the horns.
6	The mage’s tongue becomes longer and forked
7	The mage’s teeth become sharp and pointed
8	Thin scales grow in patches across the mage’s body
9	The mage grows a long, thin tail
10	Horrid, unhealable pustules grow on the mage’s face
11	The mage smells of brimstone
12	One of the mage’s hands transforms into a tentacle. This does not affect spellcasting.
13	One of the mage’s hands transforms into a crab claw. This does not affect spellcasting, but the claw cannot grasp weapons; the ability to grasp objects varies.
14	The mage’s feet become hooves
15	The mage’s legs become digitigrade
16	The mage’s flesh continually rots, dripping fluids, becoming foul-smelling, and sloughing off easily
17	The mage develops a hunchback: treat the mage as always having at least one encumbrance level
18	The mage acquires a constant cough or other malady and permanently loses 1D4 Constitution
19	The mage gains a permanent level of fatigue (what this means depends on your system)
20+	Roll twice, applying both results

 

Spiritual Corruption Table

1D12 Result	Corruption
1	Whenever the mage casts a spell their eyes glow red
2	The temperature drops, candles are snuffed out, and light provided by other sources of fire drops markedly whenever the mage casts a spell
3	An unearthly, far-distant and echoing chant, choir or series of screams is heard when the mage casts a spell
4	Milk sours, food spoils, and plants wilt in the mage’s presence
5	The mage has no reflection
6	The mage casts no shadow
7	Natural animals hiss at and are otherwise repelled by the mage
8	Insects, rats, and other vermin appear and congregate near the mage
9	A faint nimbus of flame or shadow seems to play across the mage in low light
10	The mage has an especially hideous or even demonic reflection; re-roll results of 5
11	A part of the mage’s soul is drawn off: the mage ages 1D6 years
12	Curses applied to the mage are saved against at –3
13	The mage is repelled by the holy symbols of powers opposed to their patron, and affected by any holy water
14	The mage can be turned as an undead creature of HD equivalent to their level
15	A part of the mage’s soul is drawn off: the mage ages 2D6+2 years
16	Healing magic applied to the mage has half the normal effect (round down)
17	All non-combat tasks receive a penalty of –1 (1D6), –3 (D20), or –15 (D100) if performed in sunlight; the mage dislikes sunlight and desires to avoid it when possible
18	Silver and cold iron weapons deal double damage to the mage
19	Sunlight deals 1D6+1 damage to the mage per turn of exposure
20+	Roll twice, applying both results

These signs are generally understood to be marks of black magic, unless the GM deems otherwise.  However, the signs may be concealed (e.g. strong perfumes masking the scent of brimstone), or possibly passed off as something else (such as disease or injury).  Societies where black magic thrives will of course consider such marks to be blessings.

So long as the black mage has at least one Corruption level, any creature anointed to a power that opposes the mage’s patron (or just black magic in general) knows a black mage for what they are on sight: the stain on their soul cannot normally be concealed.  Certain illusion magics may hide this, however: evil is adept at wearing the face of goodness.

Overall

 

The idea behind the tables is that at first you'll only get the lower results, since the die used is only a D12.  These just tend to mark you cosmetically, rather than truly affect you in strict game terms.  But since each Corruption level adds 1 to future rolls, things get worse and worse: corruption begets further corruption.  Eventually the mage dies of terrible wasting (Con loss) or unnatural aging (which also eventually includes Con loss).  At the same time, the mage might find ways of staving off the end: Con-boosting items and potions of longevity will be greatly desired by them.

The mage can fight against the cost of the power they're using, focusing on the advantages and trying to ignore the eventual price like many short-sighted fools (in which case it comes down to the roll each time they level up to see if they get a Corruption level) or throw themselves wholeheartedly into darkness (automatic gain of the Corruption level).  But the more power they want to wield (more spells, and more powerful spells), the more Corruption is gained, and there's no way to use any meaningful amount of the power and remain untainted.