[...Tenka... Yeah, there is Tenka. It's at the point where Sousei doesn't know how to quantify his relationship with Tenka, beyond "partner". But he does nod.]

...Yes, I grew up with Tenka. His family took me in as a child.

[...]

So in that sense, we are family. [he admits it slowly, as if it's difficult to say, and in a way, it is--but Kousetsu...is someone who would understand his slight hesitance, his struggle with the idea, he feels. It's easy to have a conversation like this with him.]

As for you--regardless of the way in which you became siblings, you are undeniably family.