This genius inventor is the one who builds the robots for White Bomber, Blue Bomber, Red Bomber and Yellow Bomber, so that they can destroy the evil beings. Dr. Gray Bomber is the grandfather of Blue Bomber, who helps him build the robots which are kept in his laboratory. His teacher and mentor, Professor Bomber, was the one who taught Dr. Gray Bomber and Dr. Shadow everything about mechanics and technological science. Dr. Gray Bomber is quite lively and active for an old man, and has an optimistic view on things.