#uralis arc

This is a funny bit the anime added, but I think it's slightly out of character. In the manga, Kahaku's motivation is split between doing what the Guardian's want—keeping Fushi under their control—and actually helping people like Fushi wants, with a heavy leaning toward the prior. He starts out by saying that "the Guardians' Fushi" can't be captured, and then segues into his explanation that they can't help anyone if they're stuck. Kahaku doesn't think he has to hide the Guardians' goal from Fushi, like he does in the anime when he edits himself. That would imply that he's on some level aware that what the Guardians want to do with Fushi is wrong, and that Fushi would not approve, which we later see is not at all true.

Kahaku, if you remember, is a big fan of the kind of true love he reads about in books, and that frequently informs his treatment of Fushi, especially Fushi-as-Parona. As to how this happened... I'm pretty sure his fondness for this trope comes from the complete absence of affection in his life before he met Fushi. Of course he would dream about meeting someone who loved him immediately, unconditionally, and vice versa. He's so attached to this concept because it got him through his whole life until this moment, so he can't bring himself to throw it out. His only feasible choice is to throw down the gauntlet and announce that he really does love Fushi even if they're a boy.