For just under half of the series the main adversary of X-Rider was Government of Darkness' Chief of Security, Apollo Giest (Apollo comes from Greek mythology, Giest is German for ghost).
The human form of Apollo Giest was played by Yuchida, Yasuhiko who would later play Watabe, Go/Zushiiin in Ch˘jin Bibyun. Stuntman Nakamura, Bunya wore the costume. From episodes 8 (Apollo Giest's first) through epsidoe 14 Apollo Giest (height 185cm, weight 75kg) carried a double-barreled black gun, "Apollo Shot" and a sun-shapped shield, "Geist Cutter". In episode 14 Apollo Geist is killed. In episode 16 a revived Apollo Geist (height 190cm, weight 85kg) is given a new shield and his right arm is replaced with built in spear and triple-barreled gun called, "Apollo Magnum". Apollo Giest was finally destroyed in episode 21.