#otani

Because ultimately it's his empathy that makes him so scary because if you wrong someone he cares about he will hunt you down to the ends of the earth to kill you (Kenkichi, Kiroranke) and, by that metric, if you help him or he comes to care for you he will lay down his life to be there in your time of need (Asirpa, Huci, Inkarmat, Nihei, Beniko, Cikapasi).

It's his sense of deep empathy that makes his dynamic with Ogata that much more interesting because Ogata refuses to empathize with anyone as doing so would force him to think outside of his own perspective when he believes everyone should think exactly like him. So when they're around each other it's a match up with the most empathetic character vs. the least empathetic character in the manga.

That's why Ogata singles him out and tortures him all the time but it's not just for conflict sake, it's because Tanigaki empathizes with his situation. He looks visibly uncomfortable when Tsukishima brings up the fact that Ogata was being harassed by his fellow soldiers for being the son of geisha. Tanigaki empathizes with Ogata and Ogata goes out of his way to punish him for caring. That's why Otani as a ship hits so hard.