[Seto's face lights up when Luna starts discribing Ren so it's clear she's hit the nail on the head.]

Yeah that's her! [Are they friends?] A-and the boy with black hair is Crow, my best friend. I don't know how long I've been gone so I wnat to make sure they're okay.

[Day and night changes didn't matter too much back home beyond the need to get to a place they could light a bondfire and sleep. So he hasn't been keeping track of the days here and vanishing threw Seto off even more.]