When I was playing Arc2, because of the lack of detail, I was like Genzou was crying over the fact that he killed his friend Orlam. (Though Genzou treat Orlam so bad, I do think he maybe, maybe think Orlam is a friend of his)
So complicated, just like Carrot said. Or maybe it's crying for Iggy who finally could be out of the painful situation he's in? Crying for being able to save his dearest love? Or similar to what I said in the first paragraph, Genzou cried for killing one who he had been bullying at best, but had never thought of letting him actually die.
Complicated, that's why it's called a story, right?