Your alts are effectively your children/apprentices/whatever through the Legacy. We already know that you'll be able to construct a family tree for all your characters on a server through the legacy system, so that is where the "children" will come in.
Will this have a ridiculous number of continuity issues as a result? Oh heck yes, the entire storylines will basically not make sense in terms of continuity but there you go. *shrug*
I'm not even sure how this is going to work for my characters since they're all different species. Unless I pull a Final Fantasy VIII and say
(marking spoilers for a decade-old game lol)