Lore on supernatural monster/Demon?

Their is this Demon i was reading about on Wikipedia a little while ago and i wanted to look him up again but i don't know the name. This Demon lures people who are upset or depressed into killing themselves, it can trick them and feed off their negative energy's. Then it takes that person soul, it has been related to Lucifer himself, I'm almost 100% sure the creature i was reading about is in fact a demon but if you recognize the lore around this supernatural monster and its not a demon please let me know. There's a wiki page all about him so if you think you know it would be soo awesome if you told me!