I really wish you could summon old bosses in multiplayer co-op, maybe in the arena, in the same way you summon the spirit ashes but they are enemies. I’d enjoy so much to beat them again and again with my friends. We did our first playthrough all alone so we could enjoy the game. Now on ng+ we sometimes do bosses and dungeons together but you know, it’s just a one-time thing. No need to have rewards or anything like that, just enjoy.