The Fight King was the ruler of a magical arena. He had black skin, many 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 "Morituri Te Salutamus," the Fight King's spirit can be seen rising into the sky with his arena.
The Fight King has the appearance of a decayed corpse, or a mummy with a shrunken head, who is nothing but the skeleton supporting him, and his pitch-black flesh and skin. One of his arms appears to have been dismembered (most likely in battle) and is wrapped in bandages. His left upper arm and left ankle are also bandaged. The Fight King has a large green left eye, and the right one has been stitched shut, like a shrunken head's, and a small, pale red crown floats above his head. Along with the Fight King's large golden sword, he also has an axe strapped to his back, a short sword on his waist belt, two knives in his belt and one on his right shin, and a little crossbow attached on his left arm.
- He never left his throne throughout the entire episode "Morituri Te Salutamus" despite having a modelsheet with him in standing and walking positions.
- The runes on Fight King's sword, according to Tolkien's Dwarven rune set, reads: "To fight is to live."
- His appearance seems to reference Guts from Berserk; both are missing an eye and an arm, and both wield a giant sword and have a wrist attached crossbow.
- His crown's design and how it floats above his head shows that it is likely a nod to The Fairly Odd Parents, another show by Frederator.