Roxas' peaceful mood shifted when he realized what he'd said aloud. To explain what he'd said would mean telling Zack, fully, about who he was. Maybe it was cruel of him to think so, but he only just felt like he was Roxas to him and not the-boy-who-looks-like-Cloud. He wanted to be just Roxas a little longer, instead of Roxas-the-knockoff-of-Sora.

"Back home, I'm part of another person," Roxas admitted. He drew one knee up to his chest, wrapping his arms around it and laying his cheek on his knee to look up at Zack sideways. "I have a lot of things to explain. I will, someday, but not just yet."