Massive Reskin only to serve as another experiment.

The background for this guy is this

After fighting the most important battle on Mars against his justice loving brother J, Keystone lost his ability to move his body and was rendered immobile. After being sent into space by ONE PUNCH, his body nearly disintegrated on contact with Earth's atmosphere. The result of Bionic Implants and complete bone replacement leads this metallic beast to be a devastator of mankind. Devastator Keystone stops LITERALLY at nothing to get revenge against everything that has wronged him.

Has a sniper cannon mounted on his right arm.

#J the Alakazam & Crew