thematically, it would make sense if they finally resolve the demon issue by letting it feed on them, sustainably
the people sustainably feed on the dungeon, the demon sustainably feed on the people's desires, then the dungeon grows sustainably from the demon's power
it ties in with the teachings of senshi, falin, and the dungeoneering goals of marcille
theres no reason why the demon have to feed on ALL the desires of the dungeon lord, the one case of the captain, it have shown that it doesnt need to eat all desires, nor is there only one dungeon lord, they could pass down the dungeon lord title hereditary