|This article is about a/an ally in Uchuu Keiji Sharivan.|
Guard Beast was originally Space Sheriff Gencer and partner to Aileen. He was listed as KIA while infiltrating the mafia undercover, but this was to solidify his cover while he inflitrated Neo-Madou in secret. His mission was so top secret that only he and Aileen knew about it, which lead some to believe that Aileen was a spy. He volunteered to be remade into his Makai beast form as it was the only reliable way to get close to the Neo-Madou boss. In this form he specializes in fighting by using gun and sword. While undercover he served as the bodyguard of General Gyrer. During a mission he came into conflict with Seigi, Space Sheriff Estevan, and Kai Hyuga, the current Space Sheriff Sharivan, only to be saved by Aileen last minute by having her place him in an dead-like state. Growing suspicious of Aileen's interest in Guard Beast's body, Kai sent Shishii to preform an autopsy on him. Shishii found that he was still alive, and when Aileen learned of the autopsy she raced to Guard Beast, revived him, and allowed him a means to escape. Later he meets with Kai, who had learned the truth of who Guard Beast was, and explained the situation. Guard Beast was later killed by an explosion set off by Seigi while protecting Kai. His last words helped Kai learn what it truly means to be a Space Sheriff.
- In Aileen's phone, his name is registered as "J". Either "Gencer" was romanized with the letter "J", or if his real name starts with it, was not revealed.