there is a boss for every type of enemy except undead bks are not really bosses
construct rom twins
gremlin seerus
fiend lord vana
jelly jelly king
beast snarbolax
undead thinking still thinking none that's it none
I was thinking like a big phantom except like curse and random status and ele as a weakness I think it would be cool to have one but you don't have to take my idea but here it is
Technically, Vanaduke isn't actually fiend, he's not entirely weak to piercing and not resistant to shadow.
Plus, you can't really just drop in a new boss: you need to have a level built around it, put it in a mission etc.
Also, curse is kinda reserved for special cases (i.e. black kats and shadow lair), so that may not work.
But yeah, new bosses would be pretty cool, but we STILL haven't resolved the cliffhanger at the end of DaN!