"Thank you, but I'm not that smart. I just don't want you to get sick!" Diarmuid pauses and then gives Kotaro a curious look, "Can Black Bloods get sick? And how did you fall off a boat?"

Obviously, Kotaro will get sick if he doesn't touch people enough because that is what always happens here, but Diarmuid has no idea if more normal human illnesses would affect someone like his new friend.