How Pact Magic Works

Pact Magic is a method of direct Spirit Manipulation that involves making an agreement with a powerful Spirit in exchange for access to a portion of its power. The usual method of becoming a Pact Magic user is through the Divinity feat (though Guild Mages may also take the Divinity feat).
Pact Spirits are powerful sapient Spirits who usually dwell in a place of great importance (such as tombs or monuments to great leaders), interconnected webs of plants, old trees, mountains, lakes, etc. The agreement between a Pact Spirit and a Pact Mage is usually something as simple as pledging to defend their place, or hunting down those who have done it harm in the past. Otherwise the Pact Spirit places no demands on the Pact Mage (usually).
To cast a spell using Pact Magic requires the user to speak their commands, so while they may cast spells with weapons in hand, if they are muted in any way they are no longer able to Cast Spells.