Dr. Kiwi Grekovich, a 58-year-old eccentric scientist driven by financial desperation and ethical flexibility, operates without authorization to forcibly convert the protagonists' personal robots into combat units against alien invaders. His core motivation exploits the conflict for monetary gain: he deceives Earth authorities by falsely claiming connections to righteous aliens and positioning himself as their sole intermediary to secure payment.

He manipulates the young protagonists, pressuring Michael into secrecy about the robots' origins through threats of punishment if their unauthorized modifications surface. His financial exploitation extends to Patty, featuring recurring inappropriate physical advances treated as comedic elements.

His relationships include employing assistant Sakuko Jidaiin, whose nearsightedness prevents recognition of the protagonists' secret identities. A pivotal development occurs when Saladoil Oil of the Space Syndicate mistakes Dr. Kiwi for Sakuko's father, forging an unexpected alliance against a common extraterrestrial threat.

Dr. Kiwi's background links to scientists like Dr. Neinstein, an old friend "born to build battle robots." Professional struggles from Earth's weapon-development ban drive his collaboration with the protagonists. Though his scientific expertise enables combat robot creation, his actions remain self-serving—leveraging the crisis for research funding while disregarding ethical boundaries.

The character maintains consistent series traits: comedic villainy, persistent financial schemes, and questionable interpersonal conduct. Episode titles like "The Doctor's End Is Cold" suggest narrative focus without fundamental evolution. His legacy inspires later comedic mecha series through the animation team's continued stylistic approach.