The Slayer is the only hope of humanity surviving in the eternal war against Hell. With no known name or age, he fights, decimating demon forces as a one-man army. But, at times, he wants to rest, even if he doesn't need to. And a bit of time spent with his child is far more calming than any demonic killing.

UPDATE (20/07/26): I'll keep adding Revelations stuff as I keep playing and reading into the lore. For obvious reasons, this might contain spoilers.