Too early to know, but my guess is alternate universe. Although, from the way he was talking, he has the same nobility but with an alternate purpose. He said something like, "A universe where people can still die. This will be interesting." Being a champion of Life sounds great, and I can see a noble guy like Mar-Vell thinking it's what he should do. It's interesting that in this event, our heroes will be championing the cause of Death in order to maintain the universal balance.