Deep Dark fame spawns a boss the warden helps you fight

Personally I like the idea of the frame being some sort of pocket dimension prison like how Evergaol's work in Elden Ring. Instead of having you go in I think it'd be cool to have some new boss monster come out and attack the city after some ritual is performed. Given that the deep dark is all about sound I think the boss would do well as something that attacks sight, maybe it inflicts blindness when too close? This could force the player to team up with the warden to fight it. Using sound direction to guide the warden to do its job since their blind anyway the challenge becomes dodging boss and warden while guiding them to fight one another. Just a cool idea I had.