Rat King (Mirage)

The Rat King makes his first appearance in Tales of the Teenage Mutant Ninja Turtles #4 as the story's antagonist. After residing in a swamp for several months, the Rat King (who remains unnamed until the end of the issue) decides to venture into a nearby abandoned industrial park and use it as shelter against the oncoming winter. There, the Rat King happens upon the Teenage Mutant Ninja Turtles and their friend Casey Jones, who had come to the industrial park to train. Believing the Turtles and Casey to be other "monsters" who wish to take his territory, the Rat King proceeds to stalk them throughout the park, even capturing Michelangelo and leaving him to be devoured by the rats (Michelangelo later escapes). The Rat King is eventually defeated by Leonardo who, in a duel with the Rat King, flings several shuriken at him, which impale the Rat King and knock him off balance, sending him plummeting into the bowels of a silo.

In the multi-part storyline "City at War", the Rat King appears in a major role. After entering the silo where Leonardo defeated the Rat King, Splinter falls into a pit and injures his leg; left helpless, Splinter is found by the Rat King, who appears before him multiple times throughout the story-arc, often debating philosophically with him and giving him cryptic advice in dreams. Splinter soon has a dream in which the Rat King appears before him as a demonic rat-like entity, and tells him to devour a rat to regain his strength. Rat King also tells Splinter that eating rats has allowed him to "find what he was looking for", and also states that he had been waiting for Splinter to come to him for some time. Two months later, after the Rat King stops appearing to him he gets enough strength and leaves the silo. Splinter finds, much to his surprise, the heavily decayed corpse of the Rat King buried under rubble, its limbs twisted and several shuriken embedded in it.

After several years of absence, the Rat King (in ghost form) reappears in a brief cameo appearance in Teenage Mutant Ninjas Turtles Vol. 4, watching as Splinter succumbs to a heart attack and dies while retrieving milk from a refrigerator. Much of the Rat King's origin is later revealed in an issue of Tales of the Tales of the Teenage Mutant Ninja Turtles Vol. 2; the story reveals that a group of beings known as the Pantheon exists, with each member of the group having jurisdiction over a species of animal. When the Pantheon member who rules the rats time reaches an end, a new one is chosen, a scarred and heavily bandaged (explaining the Rat King's appearance) patient at a hospital. Becoming the Rat King, the man challenges Splinter to a battle, which he loses after a long fight. With the Rat King defeated, Splinter is offered to take his place in the Pantheon, which he refuses. Accepting Splinter's decision, the Pantheon and Rat King leave, though not before stating that Splinter will be offered membership in the Pantheon one more time, at the moment of his death.