Star Energy Mecha: Cancer Boy

The fifth era of the universe: Before the catastrophe, humans and machines (omnics) were interdependent, and humans used omnics to become the overlord of the universe. While exploring the unknown star territory, the omnics suddenly mutated, betrayed humanity, and turned their guns on humans. Humanity, which relied heavily on the omnics, was brutally massacred, and its population dropped from hundreds of billions to tens of billions. The Blue Sea Star Federation was paralyzed. When it was invaded by the three major races in the universe, and at the critical moment of human survival, at the last line of defense of the solar system, a golden ray of light shone on a man called Pan by humans. Pan, who was as big as a blue sea star, wiped out the vanguard of the invading army with two axes, severely damaged the main army, and protected the solar system for ten years at the cost of the disintegration of his body's energy.