Fight king

The Fight King was the undead (now deceased) ruler of a magical arena. He had black skin, lots of weapons equipped to his body, and a red crown. The Fight King's Sword had the power to summon Gladiator Ghosts and was used to imbue Finn with "his favor." He tricked pairs of warriors into fighting his Gladiator Ghosts, and then eventually forced them to fight and kill each other; he seems to enjoy this very much. He also appeared to adore Finn. He met his demise when Finn tricked him into handing over his sword, and broke it. Fight King shriveled up and died, because his life was connected to the sword. At the end of the episode, the Fight King's spirit can be seen rising into the sky with his arena.