Ink Killer / Entity Killer idea.
So, I haven't put a large amount of thought however. A killer who is similar to the doctor in play and could be fun and unique would be an ink blob. Whenever he hits a survivor, he marks them with ink which infests their body. They leave behind puddles of ink (like blood) and can possible have another use when he activates his ability. I was thinking you can spend 30-60 seconds cleaning yourself of the ink or just ignore it. However, if you bump into another survivor or touch a gen. You contaminate it. So other survivors who work also get ink. Perhaps a 10 second polish time to get it off of a gen. Or something of the sort. Not sure of the exact specifics but it could be a fun twist on the horror of ink.
Another one would be Soul of the entity or something similar. The character, god please, could have a reaper design . I was thinking it would be cool if one of his abilities, however i have no idea how to balance. Would be when he hooks a survivor. He can preform an action on them. Causing a debuff of some sort for the rest of the game on their end, however a debuff to him against that survivor on his end. (Not sure how to make that work but would be interesting).
I'll think more up. Maybe actually put real effort into it at some point.