I don't know why... but seeing Yuuyake's parents in that one page made me think about something... how are they dealing with the psychological trials of long-term space travel?
I mean... they don't even have access to sunlight, well I think at least.
I say this, but I do think I know the answer... mages' minds simply are different, considering what we know about the major reason for mages' deaths, and that their immortality is connected to their mind... maybe they simply... are not affected by the same biological and psychological necessities humans have.