Magic comes from gods and demons who are capricious and unconcerned with your character’s flyspeck of a life. Those who would use magic are Summoning magical energies is arduous, expensive, and dangerous. No wizard does it lightly. As a result, there are no mundane magics, no spells used simply to light a corridor, for example. Use a torch, fool; it is much safer!

Kinds of Magic

Wizards and clerics tap into different kinds of magic. Wizards specialize in the better-known fields of black magic, elemental magic, and enchantment. Clerics receive the direct assistance of their gods in a style of magic called idol magic, which may or may not be similar to the powers of wizards.

Black magic is learned from demons’ lips. It includes witch-craft, shamanism, and totems, as well as necromancy, diabolism, mind control, and other concentrations of negative energy. Black practitioners hold power over mortals but are slaves to their demonic masters. Cthulhu cults practice black magic, as do zombie masters, witches, and voodoo shamans. Binding and summoning are considered black magic.

Spell Checks

When your character casts a spell, you roll 1d20 and add your caster level, and apply your luck modifier. This is called a spell check. You also add your Personality modifier if you are a cleric or your Intelligence modifier if you are a wizard. Wizards also apply modifiers for wearing bulky armor, and there may be other modifiers specific to certain situations.

Compare the result to the casting table for that spell. In general, your spell succeeds if your spell check is equal to or higher than a base DC of 10 + (2x spell level). The higher you roll, the more extraordinary the result, according to the casting table. 

A novice wizard cannot cast magic beyond his comprehension, but he may attempt to cast a spell of any level he has learned. This means he may attempt to cast spells where he suffers a significant chance of failure, based on his spell check modifier. If he judges the attempt worthwhile, so be it; but there are consequences to failure.

Critical successes and fumbles: A spell check result of a natural 20 is a critical success. The caster receives an additional bonus to his check equal to his caster level. Compare to the casting table for that specific spell for the result.

A spell check result of a natural 1 is always a failure. A result of 1 may also result in corruption or disapproval, as described below.

Concentration: Some spells require concentration. While concentrating, a wizard or cleric can take no action beyond walking at half speed. Combat damage, a fall, or other significant interruptions require the spellcaster to make a Will save against DC 11 or lose concentration.

Spell checks by other classes: Foolish warriors have been known to read magical scrolls in dangerous attempts to wield magic. A warrior, thief, or other character untrained in magic may attempt to cast a spell from magical instructions he encounters. A character from an untrained class rolls 1d10 for his spell check instead of 1d20. He does not add any modifier for an ability score or caster level. A trained thief may roll a higher die per his class abilities.

Saving throws against spells: In general, a saving throw against a spell effect uses a DC equal to the spell check. For example, a color spray cast with a spell check result of 17 requires a Will save of 17 or higher to resist. If a spell does not specify a specific DC for a save, the save is made against the spell check result.

Reversing spells: Some spells can be reversed to perform the opposite function for which they were intended. For example, mending can be reversed to tear an object, or enlarge can be reversed to shrink an object. Although spell reversal sounds simple and straightforward as a concept, think about it in practical terms. It’s not that easy. To use an analogy, can you un-cook a chicken pot pie by following the instructions in reverse? No. Magic cannot be simply reversed. To reflect the difficulty of reverse-spellcasting in practical terms, reversed spells require the caster to make the spellcheck with the next lowest die in the dice chain.

Spellburn

A magic-user can harness more magical energies if he is willing to make mortal sacrifice: offer part of his soul to a demon, foster a demi-god’s greedy growth by leeching his strength, or even burn the very life energy in his own cells. Before rolling any spell check, a wizard may declare that he will attempt spellburn. In attempting spellburn, the wizard temporarily expends points of his Strength, Agility, or Stamina score to enhance his spell check. For every ability point he expends, the wizard adds +1 to his spell check.

For example, a wizard in a life-or-death situation may need absolute certainty that his next spell functions. He calls to an archdemon with whom he has had past dealings. 

In offering the demon a share of his life-force, he trades 7 points of Strength to give himself a +7 bonus to his next spell check.

Ability scores lost via spellburn heal back at the rate of 1 point per day that the caster does not spellburn again. 

Automatic criticals: There is one additional option for spellburn. A wizard who sacrifices a full 20 points of ability scores in one fell swoop automatically treats his next spell check as a roll of natural 20.

Losing and Regaining Spells

Spellcasting is draining. A spellcaster can exert himself a finite number of times in one day before he is exhausted and unable to cast another spell. Depending on the kind of magic, this can be a reflection of mental recall, godly favor, access to a demon’s plane, soul-drain, magical ingredients, or other factors.

Each spell’s casting table will indicate “lost” or “not lost” in each result entry. A result of “lost” means your character cannot cast that spell again in that day. “Not lost” means the character retains the use of that spell. Generally, only wizard spells are lost when a casting fails.

Clerics suffer a different difficulty. Each time a cleric fails to cast a spell, he suffers a cumulative increase to his natural disapproval range for the balance of the day. More information on this penalty can be found in the cleric class description.

In general, spells are regained within a day of being lost. The exact trigger depends on the magic in question. White magic is regained at the next sunrise; black magic upon the moon crossing the sky in full; demon magic after a full eight hours of rest; divine magic after resting and praying to the cleric’s god; and so on, as agreed between player and judge based on the nature of the character’s magic.

Mercurial Magic

The firstborn son of a witch hanged at trial wields black magic adroitly. An orphan raised by satyrs is a precocious student of druidry. Cosmic caprice determines skill in magic: birth order, family lineage, horoscope, and matters even more abstruse have as much influence on a wizard’s spell-casting as his hard work and native intelligence.

As a result, the effect of a magical spell varies according to who casts it. A magical rite invoked by one mage may be more powerful – or even different – than the same ritual exercised by a peer. These variegations are not predictable, as the subtleties that produce them can never be fully catalogued.

The mercurial nature of magic is reflected in game terms. When a wizard learns a new spell, he rolls on table 5-2 to determine how that spell manifests in his hands. This percentile roll is adjusted by his Luck modifier x 10%; i.e., a +2 Luck modifier counts as +20% on the check.

The player rolls on table 5-2 for every spell he learns, and the effects are specific to that spell.

Corruption

Low-level wizards are powerful. High-level wizards fear for their souls. Continual use of magic results in…changes. Exposure to demons, radiation from other planes, elemental energies in toxic quantities, and the servants of Chaos all affect a wizard over the course of his career. Higher-level wizards seek pacts with demons and elementals to sustain their health so they may continue to advance.

Each and every time a wizard rolls a natural 1 on a spell check, he suffers the effect of the spell failure. Moreover, his spell may misfire and he may suffer corruption. The individual spell entries include specific results associated with a natural 1 on each spell check, as well as misfire and corruption results specific to the spell. Some results will further direct the player to roll on one of the corruption tables: minor, major, or greater. If this is required, the roll is 1d10 minus the spell’s level plus the wizard’s Luck modifier. In select circumstances, other modifiers may apply as well (e.g., a curse). Certain kinds of black magic may trigger corruption more often, as indicated and adjusted by the spell table.

Luck to avoid corruption: A wizard that suffers corruption may burn a point of Luck to avoid the corruption. The Luck can be burned after the player rolls to determine the specific corruption result. Note that Luck cannot be burned to avoid a spell misfire, only to avoid corruption. Patron taint is considered corruption for these purposes.

Tables

Table 5-2: Mercurial Magic

The complete rules for mercurial magic are in the DCC RPG core book. See that for more info!

Table 5-3: Minor Corruption

Table 5-7: Disapproval