Genryūsai is a legendary ninja and founding elder of the World Ninja Association (WNA), projecting tranquility in daily life despite his formidable status. He mentors Van following the injury of Van's father, guiding the young ninja's training, investigations into the gum-like alien Space Ninja threatening Earth, and battles against them. Genryūsai is the quieter, more reserved twin brother of Gen'unsai, their bond reflecting the series' broader ninja heritage. Beyond Van, he leads WNA-affiliated young ninja students in probing the Space Ninja phenomena, acting as a central figure coordinating efforts to understand and counter these alien threats.