Buying My Way Through the Multiverse

In a dead world overrun by walkers, Gray gains access to a system capable of buying almost anything: weapons, skills, powers... even abilities from other universes. At first, surviving The Walking Dead seemed simple enough. Then he discovered Rebirth. A feature that allows him to travel between worlds while permanently keeping some of the powers he earned. Now, every apocalypse, every universe, and every battle is a stepping stone toward something far bigger. And Gray plans to survive them all. First time doing this, so don't expect award-winning writing. Might also mess up timelines or places but just take it as an AU :) — Description from novelcodex.org