If TMNT can be said to have a theme, it is that of fathers and the effects they have on their children. In contrast with the original animated series, Splinter’s parentage is made into a major part of the series, and several other characters gain additional storytelling weight by serving as mirrors to that relationship. This, more than anything else, is why I really like the idea of Karai as the Shredder’s daughter, as problematic as her demotion can be.
Most of these, I should note, are cases of adoptive fatherhood, which brings up the secondary theme of the series, which is that family is not inherently biological. The Hamato line, in particular, is, as far a we know, continues only via adoption, and will continue to do so, given the biological realities of the turtles.
In any case, the list. If I’ve missed one, or you simply have something to say, feel free to bring them up in the comments.
- Splinter (father to Leonardo, Donatello, Raphael, Michelangelo)
- Oroku Saki, a.k.a. The Shredder, a.k.a. Ch’rell (father to Karai Saki)
- Arnold Casey Jones Sr. (to Casey Jones)
- Harry (to Nano*)
- Hamato Yoshi (to Splinter*)
- The Daimyo of the Battle Nexus (to The Ultimate Ninja)
- Doctor Dome (to Ananda)
- Ammag (to Kluh)
- The Ancient One (to Hamato Yoshi, Yukio Mashimi, and Tang Shen)
- Mr. Hambrath (to Starlee and Glaxor Hambrath)
* Although the “children” in both cases see these people as their fathers, it is unclear that they would describe the relationship in that manner.