Overpowered Bodyguard Moving Throughout the Battlefield

Rex is a monster. No really. He's a fucking menace. His mother is an internationally renowned terrorist. He himself is a part of that syndicate. He's known as the strongest being on the planet. Nothing stops him from destroying the world outright. Nothing but his conscious. No one has seen his face, but many speculate that he hides in the open. Maybe the thing holding him back is his foster mother. She really is just the sweetest thing. Died because her... Yeah, but she really was a nice person when she was alive. Maybe it's the job he got through his foster father. Who gave him a bodyguard job for the worlds' greatest mafia family's crown princess... Or maybe it's the fact that life isn't enough to be worth it, but also not enough to quit? Maybe he's just mental. That might explain it. But while he's figuring things out, why not have some fun? (AN: If I leave, it might be a while, but I will be back eventually, and it will be finished.)