The writers seem to like repeating the pseudo-romance theme between an older guy and a younger guy. There's also always a woman, a sister of one of them, who is attached to both of the guys. And then the older guy sends the woman to a bloody, violent death, and the younger guy is torn between grief, desire for revenge, and the pseudo-erotic attachment to the older guy.
I don't find the yaoi theme disturbing, but it bothers me that the female becomes some sort of human sacrifice. It's almost as thought the woman must be sacrificed so that the two men can fully realize their feelings for each other. Very disturbing.