Titan

Jason AKA Titan was a US solider in WW2 who sacrifed himself for his unit by landing on a grenade. shrapnel ripped him apart and tore through most of his body, but he was also a part of a secret experiment called operation phenoix which involved injecting serums into kids to increase their physical and mental capabilities. with his body basicly modified he was able to miraculously surive and reach a special operation unit which had to install cybernetics in his body to keep him alive. His lower half was completely exchanged for the prostetics and his arms were gone as well. they put him in cryo sleep to let his body adjust. However while asleep the germans infected the world with a zombie like virus and by the time he woke up he was all alone apart from the walking dead. For years hes been killing them maybe a decade or 2, but then he discovered a device that could transport him through dimensions and thats where you find him.