Swain mentions Beatrice in his VO

http://www.surrenderat20.net/2018/01/123-pbe-update.html

at minute 2:58 of the VO youtube video he says "Which one of you is Beatrice again?" If you take into account other lines like "I conquered the demon" I think Swain got the demon's power, but the demon itself is just a "force" Swain uses, not actually a sentient being