Sorry, but there is a reason there is only female companions (other than yuri). I don't mind if guys are used as Npc's along the way, but not within the group. Ya know, otherwise big baddy demon will sense the deal is broken and Japan gets destroyed. No budging on this. At all. It wouldn't be fair to the other gentlemen who wanted to join.

And does the demon take over whenever they want? Like *pops up and fire!!!* or limited to once per day or something?

And yeah I suppose that physical weakness will do