Responses
Oh
Oh dude
That would make so much sense
me too, It would be so awkward .. and remember the memories tanjiro see about a swordsman and a coal burner. The swordsman was saying he loses someone important.
When First Moon said "Demon Hunters Brother, How Nostalgia," I wonder if he was the brother of the first breath fire demon hunter. If so, that would explain why he looks like him, and even has similar hair style. There's no way Muzan would be willing to turn a guy who's been hunting him like crazy into a demon. Unless he turned the brother who was a demon hunter.
This is all just a theory.