Some TMNT stuff really isn't for little kids.
In the Teenage Mutant Ninja Turtles & Other Strangeness role playing game by Palladium Books, Otto Rattus is the personal bodyguard and chauffeur of the recurring villain Dr. Victor Oban Feral. He is a core BIO-Spawn character, and also has roles in scenarios published in Teenage Mutant Ninja Turtles Adventures! and Teenage Mutant Ninja Turtles Guide to the Universe.
Otto appears to be a middle-aged human man, but he is actually a mutant rat whom Feral has raised since he was a lab animal, and treated extensively with drugs, bionic implants and surgery to allow him to pass for human. In spite of this, other mutants can instantly tell he's actually a rat.
Otto is the only one of Feral's mutant servants who wears no control collar.
Otto is the only non-human Feral treats with love, and in turn, Otto's loyalty to Feral is absolute, and he will do anything it takes to protect Feral and his interests. Unlike Feral, Otto is genuinely mean-spirited to his enemies. But like Feral, Otto has a public identity and cannot afford to commit crimes that can be traced back to him or Feral. And unlike even Feral, Otto has no criminal record at all.
Otto is a devoted and involved fan of horse racing.
As a personal assistant to a man like Feral, Otto's skills are numerous—he can fight, he can play various sports, he's a modest polyglot, he can fly small aircraft, and he can readily assist in Feral's secret underground vivisection laboratory.
Otto is also super-strong thanks to his bionic implants.
Otto Rattus was born an ordinary lab rat, and was given to a 16-year-old Victor Oban Feral as a pet. But Otto didn't remain ordinary, and through Feral's experiments he became a mutant. Additional drugs, bionic implants and surgery drastically altered Otto's appearance to make him pass for human. As Feral became a successful scientist and wealthy businessman, Otto has remained his loyal servant.
Otto's TMNT&OS profile lists him as 42 years old, already much older than the natural lifespan of any non-mutant rat.
- Feral and Otto's backstory does not align with their respective ages. Feral is listed as 66 years old, while Otto is listed as 42 years old (an age difference of 24 years), but their backstory makes it clear that Feral first received Otto as a pet when Feral himself was 16 years old, requiring Otto to be at least about 50 years old or Feral to be at most 58 years old for the backstory to work as written.
- Though Otto is a recurring core BIO-Spawn character, he is the only one of the core characters who has never been given official artwork in any of the Palladium RPG books. However, a figurine of his character was sold as part of the Dark Horse Miniatures.
- TMNT&OS misprints Otto's weight as 2331 lbs.