Yuta didn’t know that yet - Thirteen had taken him at the beginning of that fight. So the suggestion had him raise his eyebrows at him. Why would Nanami ask that?

Still. “Probably? I’d need a bit of his blood - that’s also something people don’t really know. Gojo-sensei does, though, and he’s never offered.”

Plenty of sorcerers and curses detailed everything about their abilities in a fight to increase its strength. Yuta didn’t need to do that, thankfully. It gave him a huge advantage, and it’s not one he wanted to give up just for a bump in power he didn’t need.

Yuta didn’t see himself fighting Nanami, though.