Known variably as Koen or Cowen across sources, this scientist serves as a primary OVA antagonist. He previously collaborated with Dr. Saotome on Getter Energy research. Alongside associate Mr. Stinger, Koen becomes convinced that forced evolution via Getter Rays is Earth's future. This belief drives them to willingly embrace symbiosis with amorphous alien Invaders, merging their bodies with these entities as a desirable evolutionary step.

Following this transformation, Koen and Stinger actively assist Dr. Saotome in threatening humanity, sharing his conviction that the Invaders, compatible with Getter Energy, are Earth's rightful inheritors. As key figures within the antagonist faction, Koen participates in pivotal events: the reactivation and evolution of the Shin Getter Dragon, a massive Getter Ray-powered weapon, and later, the plan to transform Jupiter into a new Getter Ray source and hurl its moon Ganymede toward Earth. Koen's involvement remains confined to this OVA narrative.