Kamen Rider X appears in "Kamen Rider SD" as a super-deformed alumni Rider. Originally engineered for aquatic combat, he wields the multipurpose Ridol weapon. He operates within a squad alongside Kamen Riders V3 and Super-1. A defining trait is his profound compassion for small, vulnerable creatures; during one mission en route to battle, he deliberately delayed his team to avoid crushing insects like ants or flies, valuing their lives as precious. This underscores his protective instincts toward even the smallest life forms. He pilots a modified Cruiser motorcycle. In the video game "Kamen Rider SD: Sortie!! Rider Machines," he is playable in a sidescrolling vehicular combat scenario.