Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General Source Hunters from the first D:OS

"Source" isn't an inherently bad thing in the Divinity series. It was corrupted during the time of D:OS1 due to the situation with Astarte and the Void Dragon, but at some point after that it returned to its original, generally beneficial form. It's likely that the order of Source Hunters would have disbanded sometime thereafter.

However, the big bad guys in the setting have a tendency to mess with it in various ways when they show up. This was occurring during the time of Divine Divinity and appears to be happening again a short time later when D:OS2 begins.