Master Splinter

Master Splinter is the adoptive father of Leonardo, Raphael, Donatello, and Michelangelo. He raised them and taught them in the art of Ninjutsu. He is portrayed as a dark gray rat in monk's robes and is stated to weigh 90 lbs.

Splinter started his life as an ordinary rat in Japan who found his way into a home owned by the Ancient One. When he was discovered, his life was spared by Tang Shen, the Ancient One's adopted daughter, who took him as a pet. As in previous versions, Tang Shen became tragically caught up between Hamato Yoshi and a jealous rival, this time Yukio Mashimi, a childhood friend of Yoshi's. The two of them eventually joined the Utroms and became Guardians. But Mashimi's jealousy of Yoshi, both for his advancement as a Guardian, and the love of Tang Shen, led him to murder Shen and betray the Utroms' location to The Shredder. Yoshi killed Mashimi in revenge and went to America with the Utroms, taking Tang Shen's pet with him, and giving him the name Splinter. Later, Yoshi would be tracked down and killed by The Shredder, who tried to force him to reveal the Utroms' location. In this continuity, it was Hun that Splinter scratched as his master Yoshi was attacked, and not Shredder.

Soon after he found the TMNT and trained them in the way of ninjutsu. When they were older, Splinter named the four turtles, from a battered book he fished out of the storm drain containing the names of Renaissance artists, which he named the Turtles after. He continued to train the Turtles in every way they could, for preparation for evil the TMNT did not fully understand until The Shredder Strikes Part 1 in which the TMNT learned of the Shredder's evil and hatred and how he killed Splinter's master, Yoshi. The Turtles then forward continued to fight the Shredder to stop any evil spreading across New York and the world.

Ninja Tribunal
Splinter appears most of the time alongside the Ancient One expressing his deepest concern for the safety of his sons and for the harsh teaching methods of the Ninja Tribunal when they enlisted them to fight Tengu Shredder. He has nightmares of his sons dying in battle and was grief-stricken when it appeared to come true. To his relief, his sons were merely knocked out and defeated the Tengu Shredder.

Fast Forward
Splinter has been seen in the Fast Forward season continuously teaching his sons' and Cody Jones the ancient ways of Ninjutsu  and despite how old fashioned he's shown to be in previous seasons, too adjusted to living in the year 2105 fighting off any evil that came his way alongside his sons and cody.

Back to the Sewer
Splinter did not make much of a physical appearance in Back to the Sewer, however he did appear as small data fragments scattered across Cyberspace thanks to Viral and the only times he was every physically shown was during the first episode of BTTS called Tempus Fugit when he was first scattered into a million data pieces and the last episode called "Wedding Bells and Bytes" when he was returned to the real world and attended April and Casey's wedding ceremony which was abruptly interrupted by the appearance of "Cyber Shredder". Though he did appear in a few flash backs. Splinter is shown to love his sons very much. Splinter's design was also revamped to make him look more like his design in TMNT.