Knight Heavyarms transforms into a gigantic machine soldier-sized giant that combines the strength of the gundam clan with the special abilities of an android. Possessing abilities comparable to those of Armor Fighting God, it blasts away the vassals and monsters of the Genesis Army OZ World. While its entire body is a heavy weapon, its bullets are psycho bullets, crystallized from the passionate heart of its warriors through mental strength, so it never runs out as long as its mental strength lasts.
The camaraderie it developed with Wing, who it fought alongside, exploded when Wing was petrified, reviving the machine god's heart.
Equipped with a giant cannon provided by Arms Dealer Howard, Mecha Fighting God Heavyarms is powered up. It reacts to Trowa's Axe of Lion and blasts away the Genesis Army OZ World with a roaring cannon resembling a lion's roar.