Splinter is a more elderly rat than seen in most other incarnations and is the adoptive father to the four 18-year-old Turtles. He is the former pet rat of Hamato Yoshi. Also in this incarnation Splinter is a calm, wise master, who always has a wise saying on his lips, but also often fights personally with the Turtles against the Dragon Lord and his Rank Warriors.
During his spare time, he is seen meditating in a supernatural dimension known as the "Realm of Dreams" and plays chess with a blind man named Andre, whom he invites to live with him and the turtles, when Andre is evicted from his apartment. Splinter is also an old friend of a mystical Shinobi Shaman named Chung I, who warns him of the Dragon Lord's plan and demands of Splinter's release when he is kidnapped, unfortunately at the cost of Li's own life.
In the first episode he is being held captive by the Dragon Lord in the realm of dreams, but the Turtles learn to dream walk thanks to Venus de Milo and finally liberate their master. Splinter remains in a coma-like state for a few episodes, until the turtles free him from the Dragon Lord's domain. He then reveals that he knew all along about the existence of the fifth turtle Mei Pei Chi (better known as Venus de Milo) and welcomes her into their family, as his daughter. He encourages Venus to no longer mourn Chung I's passing as he 'has gone on to a better place'.
Splinter still shows formidably and exceptional skill in combat, as he is seen easily defeating entire hordes of Foot Soldiers and Rank Warriors. The only warrior shown better to him in combat is the fierce Dragon Lord himself. Splinter still shows a sense of humor, often making jokes and wise cracks like his students when battling or simply in the comfort of his own home. Splinter does not like it when the Turtles jet through the streets on their hummer and motorcycle. In general, it would please him if they would put less emphasis on new technology and more on older values .
He was going to be shockingly killed off in the second season (most likely by the Dragon Lord), leaving the Turtles to learn how to fight without their master's guidance or presence, but it was cancelled before this could happen.