[starslayer]

Black magic in my own setting comes in two flavors.

One focuses on the manipulation of souls, it is a variant of incanting that sees much improved returns for involuntary sacrifice, the ability to extract a soul for later use, but losses the ability to make hanging rituals, or use components (stored souls work as a mobile energy source which allows pretty dynamic casting on the fly). Processing souls requires the use of torture. Since it is incanting based in a primarily RPM based world it avoids the greater/lesser divide. It is the primary magic that demons and dark elves employ, but someone looking for a shortcut to power may learn it.

The second dark magic is injury based, (called blood magic). It is normal rpm but it loses the ability to use fatigue or other outside energy sources in exchange for being able to tap any injury inflicted near the caster at 2 injury = 1 energy rate. The setting is aware of ways to exploit this and siege Wizards who use this school often have a 'splatterpault' a catapult with a fixed cage that swings into a bed of spikes loaded with prisoners or slaves to provide massive surges of energy for devistational combat spells. It is the primary magic of orcs and significantly shapes their battlefield tactics (basically no traditional siege weapons, lots of high speed raiding tactics that are built on disrupting enemy blood casting while capturing foes to use in their own (cause there are only so many slaves/prisoners you can drag along with a military force before they become a liability). Many 'battlemages' learn this variant because it synergizes well with being in the midst of combat, but the temptation to 'do it like the orcs' and engage in wholesale slaughter in exchange for big surges of power is always there for someone willing to walk that path.