[ Day's gaze trails down to where they're holding hands, because he senses Ginger trying to use them to explain. His fingers curl around Ginger's hand for a moment, as if to say that at least right now, it's Day. ]

Got that right. I guess you could say I'm...a mortal with a bunch of extras tacked on. [ Which he realises is a rather crude way of explaining it, but it makes sense to him. ] I can live pretty darn long, assumin' I, uh, don't mess up and get myself killed 'fore then. [ Hm. Moving on. ] But...not a day more than what destiny says I get, 'cause there's always an ending, accordin' to the Maidens.

The Maidens are...I guess basically, my bosses at the top of the Bureau of Destiny. They Choose the agents for their divisions when they're born, but we don't find out 'bout this for years 'til the appointed hour happens. So 'fore I joined the Division of Serenity, I was just some regular mortal down in Creation with my own life. [ And at some point he had to segue from that mortal life to a life working for Heaven. Ginger might be able to guess what that involved. ]