Sin is a form of infernum created when one commits a grievous action that violates one of several different kinds of laws, norms, or principals. Small amounts of sin usually wither away instantly, but certain actions--murder, rape, torture, abuse--create lingering sin. Learning to wield it requires further acts of violation. A user of this energy is called a Peccator.

Ritual Murder, killing to create and control sin
Sineating, absorbing sin in the holes in your soul, making it part of you
Ritual of Violation, a ritual that means every sin you commit gives you new power
Communing with the Damned, giving the damned in the Hells access to your soul in exchange for powers
Inhuman Invocation, invoking one's sins through public exposure to create an aura of damnation