i keep imagining the end of kirby 64 in the structure of deltarune chapter 4...
you land on ripple star and immediately go thru the castle bc the outside is infested to hell with dark matter (they're trying to get to SOMETHING but you dont know what). pretty stained glass bg and all that
the gang gets split up in a dark section. dedede in particular is having a Very Bad Time and then in the bro/son moment of the century, (not) bandee saves him from a possessed queen ripple (this earns him his promotion in rtdl)
the castle is starting to crumble. you climb all the way to the top. in place of the titan, you face the queen again. except she's big and cool and awesome. her power as queen allowed her to act as a living barrier and absorb dark matter to buy time for ribbon and prevent it from taking over ripple star entirely. she's a guardian. and also miracle matter now bc dark x fairy magic. wrow
adeleine and ribbon use the crystal to purify her. and then it leads into the zero two fight as normal if u collected all the shards