Board Thread:Questions and Answers/@comment-45072377-20200320051411/@comment-27648794-20200405195608

Well, after he "defended" himself from his own clan, by murdering almost everyone, together with Esidisi, he picked up Wamuu and Santana amongst the dead. He raised them after that, so maybe those two could think of him as their father, but apparently Kars must have raised them strictly as warriors, so he must have forbidden them to call him that. It feels is more like "I raised you to be useful to us" rather than "I raised you to be my dear son", and they appear to treat each other more like friends rather than family despite the huge difference in generations... Since it's implied that they COULD have adopted them, yet that word isn't anywhere at all, it's unknown how their relationship is meant to be. Having to legally adopt a child before one can live with it or raise it or be considered its father, and similar concepts are own to humans. And since the four pillar men live without rules, Kars and Esidisi could raise Wamuu and Santana freely to be whatever they wanted without "legally" being their parents or being forced to let them do something else other than follow Kars's plan. In the end, since Araki decided it was better having almost no info at all about the pillar men, and it's not known whether they lived as a family, and whether Esidisi and Kars were actually gay...

Everything depends mostly on what headcanons you think are the most believable and acceptable.