Splinter is a short and plump mutant rat with grey fur, as well as white fur in his ears, white hair with a section tied into a top bun, white bushy eyebrows and a goatee to compliment. He has golden yellow eyes, a red-pink nose, black whiskers on his cheeks, his arms and legs are pink (with his hands having five fingers instead of the usual four) and a small tear on his right ear.
Splinter wears a black hair tie to hold up his white top bun and a brown kimono with orange trim and red lotus flowers printed on the kimono.
Splinter is laid-back and very lazy as he often sits in the chair as seen in Mystic Mayhem. Not much is known about him now, but he does fight as seen in Origami Tsunami when he fights Mikey and Donnie.
Once human and now a mutated rat, Splinter is an eccentric mentor to his turtle sons, training them in the art of ninjutsu. Well, when he's not watching game shows and Lou-Jitsu movie marathons, that is! His tail is a weapon that can take on any TV remote!
- Splinter, in this series, is voiced by Eric Bauza, the voice of Tiger Claw from the 2012 TV series. Bauza also previously voiced a different version of Splinter in TMNT: Don VS Raph.
- Splinter has troubling remembering his sons' names, and even refers to them by their mask colors.
- According to an interview, the reason that Splinter looks like he's gained a few pounds, is because since there's no Shredder in the new series. Splinter has no exact reason for training the Turtles.
- However, after they learn about threats such as Baron Draxum, he begins training the Turtles more seriously.
- This is the fifth incarnation of Splinter who was once human before becoming a rat, after the 1987 TV series version, the Archie version, the IDW version and the 2012 TV series version.
- According to Leo, Splinter always falls asleep after eating milk and cake.