Umm, unless I'm mistaken angles (or divine beings) already exist or have had an influence in Rivellon although I don't remember Larian expanding on how or why or where these beings exist. In the very first scene in Divine Divinity a "Divine being" saves our hero and marks him as a "chosen one" who later ascends to a divine being and somehow retakes his mortal form.
It's been ages since I played the first game, but I remember there were multiple "chosen ones" in which the baddies hunted down and killed all but you when Zandalor saved you from the death knight.
Perhaps if Larian does a Divinity game following the timeline after the events of Dragon Knight Saga more lore or info will be expanded upon on who or what these divine beings really are.