Master Splinter

Master Splinter is the real father of Karai and Zantou and is the adopted father of the turtles.

Treating Zantou
When the turtles returned to New York they brought Zantou with them but does not tell them that he is his son becuse he dosen't need to know right now, later when he does, he treats like an enemy.

Dark Zantou Arc
When Zantou turned evil and used his dark powers on everyone, he soon regreted ​​​the way he treated Zantou, later when Zantou tried to destory the world, he decided to tell Zantou that he loves him and forgives him for the lies he told, but Zantou refused to listen and tried to kill him but his new powers prevented him from doing so, later Zantou revreted back to normal, he later started treating Zantou like a son.