Zarkov is a brilliant scientist who creates a rocket and forces Flash and Dale Arden to come with him to the planet Mongo, and fight against Ming the Merciless.
In the first Flash Gordon storyline, Zarkov discovers the Earth is endangered by an impending collision with the planet Mongo.
"[9] In this episode, Flash Gordon and Dale Arden are replaced by Batman and Wonder Woman who journey to space in order to rescue Zarkov and his assistant.
[10] The issue of Zarkov forcing the heroes to accompany him to Mongo is avoided by changing the story by having Flash and Dale come to his underground laboratory during a dangerous meteor shower that sets off a deadly volcanic eruption that traps the visitors even as it threatens to kill them.
[11][12][13][14] This version of Zarkov is a former NASA scientist, who was fired and dismissed because of his "mad" theories about an alien attack on Earth.
After capturing him, Ming reveals the only reason the Earth is being destroyed is because Zarkov recognised the catastrophes as a deliberate attack.
His nervous attitude came from the fact that after Doctor Gordon disappeared in the rift experiment, he was hounded by FBI agents to cover up the truth.