Foul Magic

Foul Magic, also occasionally known as fell magic, black magic, and monster magic, is a type of magic used by certain humans.

Foul magic is external; meaning that whatever causes it to occur (a phrase, an object, etc.) is in and of itself it’s own entity. This differentiates it from Corpus magic (usually just called magic,) which is channeled through the manipulation of God in one’s bloodstream. Foul magic is sometimes caused through Satan (monsters or monstrous artifacts, certain spellbooks) and sometimes through God (holy items, angelic items, certain spellbooks); so long as the magic does not come from within a persons bloodstream, it is considered foul.

Terminology Confusion
In-universe, the term "foul magic" is often misunderstood. Most people believe that foul magic refers to the magic of monsters and certain cults or necromancers. In reality, it just refers to any external magic. Many everyday appliances use light amounts of foul magic in them (i.e. certain expensive cell phones, which use electric magic to supplement the battery life.)