Dr. Cohen served as a key Getter Ray researcher under Dr. Saotome, first appearing human before Invader entities infected and controlled him. He operated alongside colleague Stinger, addressing him with the familiar "kun" suffix. Post-infection, both became advance agents for the Invaders, furthering Saotome’s scheme to weaponize Getter Rays globally.

Cohen possessed dark skin, large lips, and perpetually wore sunglasses, sporting blonde hair styled like a mane. Merging with Stinger into a gestalt form, his face appeared on the chest of a purple-skinned monstrous entity. In this fusion, Stinger formed the upper body while Cohen comprised the lower section with five pairs of legs and grey armored plating.

His personality reflected obsessive dedication to Getter Rays, embodying mad scientist traits amplified by Invader influence. This extended to a fervent belief in Darwinian evolution, viewing Invaders as ultimate lifeforms destined to thrive through Getter Energy. Though primarily loyal to Saotome, his actions increasingly served the Invaders' agenda.

Expert in Getter Ray technology, Cohen sabotaged global communications and orchestrated lethal traps like rigged explosives to eliminate opposing political ambassadors. He piloted the Metal Beast Poseidon. In his merged form, Cohen launched energy projectiles from his mouth using energy supplied by Stinger.

His history began with collaborative Getter Ray research alongside Stinger and Saotome, extending to the Moon where Invader infection occurred. Returning to Earth, they infiltrated the Japanese government. Facing governmental interference, Cohen severed international communications and executed ambassadors. Later, he deployed a nuclear missile to saturate Earth with Getter Rays, taunting the Getter Team during launch.

After the missile’s detonation caused global catastrophe, Cohen and Stinger battled the Getter Team directly. Piloting the Metal Beast Dragon with Saotome, they were seemingly destroyed by the Stoner Sunshine attack but survived. Traveling to Jupiter, they threw a Getter Furnace into the planet to create a Getter Ray Sun. In a final assault, they merged into a colossal Invader entity emerging from Jupiter’s flames, arguing all life evolved through Getter Rays. The Getter Team bisected their combined form with the Final Tomahawk, killing them.

Cohen’s design drew inspiration from Dr. Shot in Ken Ishikawa’s *Majuu Sensen*, reinforcing his role as a scientist corrupted by otherworldly forces.