A Villainess Survives with her Fists!

You're aware of the typical trope- girl gets transmigrated into the body of a Villainess in her favorite dating sim, and the story spins to revolve around her instead of the protagonist. But when a washed up, ex-MMA fighter turned gaming shut-in finds himself in a both another world and another body, he'll have to bend the rules to keep from falling onto the route of world-destruction!