Warren Stone was originally a narcissistic news reporter who was mutated in a worm. He was replaced and forgotten until he became a supervillain. He meets the turtles in order to become their greatest nemesis. Unfortunately, the turtles barely remember him let alone acknowledge him as their enemy so Warren decides to enhance himself using magic and becomes a buff version of himself.
The Turtles were after Hypno-Potamus and using a disguise to lure him but Warren took notice and used it to lure the turtles. After Hypno-Potamus defeats the turtles, arrived Warren decides that only he can destroy the turtles, and defeats Hypno single-handedly. During the act, he had to sacrifice his magic, reverting him back to normal.
Stuck on You
Stone attempts to destroy the turtles again, but they pay him little heed, too distracted dealing with Hypno and the Foot Clan. Close to the end of the episode, the turtles use him to tie them back together and defeat the foot and Hypno. After the Foot Clan failed to bring the other gauntlet, Warren took it for himself and decides to use its power to fight the turtles.
The Evil League of Mutants
In The Evil League of Mutants, Warren Stone joined forces with Baron Draxum, Meat Sweats, Hypno-Potamus, Repo Mantis, and the Sando Brothers to destroy Ninja Turtles after coming out of nowhere. The other mutants didn't take him seriously, but after using his gauntlet, he got their respect. After tricking the turtles to an abandoned warehouse, the league ambushed them and nearly defeated them, but they used their training to defeat the group.
Warren and Hypno, Sitting in a Tree
Warren lives in an apartment with Hypno-Potamus.
Powers and Abilities
Warren is quite durable but his healing factor takes him seven days to heal. He also uses magic to enhance himself.
Warren interfered with Hypno-Potamus' attempt to kill the turtles but the two antagonists became allies when they both joined the Evil League of Mutants. By the episode "Warren and Hypno, Sitting in a Tree", the two are revealed to have become friends, moved in together and fallen in love. They characterize their relationship as "friends/roommates/magical assistants," but are extremely tactile and affectionate with each other, very visibly treating each other like boyfriends.