Responses
He used to eat souls whenever he wanted, as seen in the past during the contract where he directly tried to trick Ciel into eating his soul. But "for a long time" he hasn't been interested in that anymore. I don't know what is "a long time ago" for a demon
I don't know why I have a huge gut feeling that's not Sebastian at all. We all know Sebastian only likes very specific souls and not the type to eat any soul so if that guy's story is true then there's a chance it's another demon