Hell Bro's is a fictional armored combatant in Kamen Rider Build, used as a powerful enemy Rider rather than a main hero. The name is presented as a single stylized title, and there is no widely established separate first and last name in the series. Hell Bro's serves as a dangerous, high-threat opponent connected to the conflict between Riders, showcasing the darker experimental side of the Kamen Rider world. Its role is primarily to challenge the protagonists in battle and emphasize the series’ escalation of power.