Wise rat master who trains the Turtles in ninjutsu and moral discipline.
Splinter is Leonardo's martial arts master and moral authority.
Splinter trains and disciplines the Turtles, while Leonardo follows his guidance during the search for a new home and the battles against Shredder.
Their bond combines training, discipline, and recurring disagreement.
Raphael lives under Splinter's leadership but disregards Splinter's orders when he recruits Keno and searches for the Foot hideout.
Splinter mentors Donatello and helps him interpret the meaning of his existence.
Donatello is one of the Turtles living with Splinter, receiving his guidance and participating in the group's decisions and battles.
April provides the Turtles and Splinter with temporary shelter and support.
Splinter and the Turtles are living with April in her new apartment while they search for another place to live.
Their conflict is the wider master-versus-enemy framework behind the Turtle battles.
Shredder vows revenge after his previous defeat, and Splinter saves the Turtles during the Foot ambush connected to Shredder's hideout.