What can be done to solve this? Lets brainstorm

some of these ideas are meant to be used in a random last stage
random last boss (several last bosses and you fight one of them each with different strengths, like one that is fast as a wind slaver or one like the current one that is a tank)
stealing from the last boss
multiple weaker bosses
a puzzle (not a fan of puzzles but just trowing it out there)
tons of traps with trying to find where the rod is
mystery system (the iocrym is already a wreck)
any other ideas?