Binding

You could kill them, I suppose. Destroy their earthly form, scatter them back to where they come from. But they'll come back. They ALWAYS come back.

Interplanar interlopers, when killed, do not die. Their mortal form can be dispersed, but a Devil or Angel whose form is dispersed merely returns to their plane of origin - The Hells for devils, and the High Heavens for Angels.
It was clear to the earliest human resistance that a more permanent method of dealing with their adversaries was required. It was with this in mind that the art of Binding was developed, allowing a mortal mage to contain the essence of an interplanar invader within a suitable container - potentially trapping it forever.

Utility

Used to permanently contain Devils or Angels. Human souls can be bound, but the practice of doing so is highly illegal.

Access & Availability

Available only to Binders of the Theligosian college.

Complexity

Highly complex incantations.