This warrior seemed to be a human being who was dressed in a spider-themed green-and-red armor. He guarded a spider that accelerated a person's age, the one that attacked both J.B. and Kaitlin. He was also Doom Master's rival, after Grimlord offered him Doom Master's job if his plan was successful. Afterwards, he sought the position and almost usurped Doom Master. In battle, Arachnobot could create high-pitched squeals (that weakened Ryan) as well as blast lasers from the spider's eyes on his helmet. He also could create web-shaped electrical blasts and wielded two swords and a trident. Doom Master intercepted his attack on Ryan and destroyed him before he could destroy Ryan and replace him using his spider plan. Luckily for Doom Master, Grimlord never found out that Doom Master was the one who destroyed Arachnobot. With Arachnobot out of the way, Ryan was able to find the spider and create an antidote to restore J.B. and Kaitlin to their normal ages.
- In Uchuu Keiji Shaider, Doom Master and Arachnobot's Japanese counterparts were actually brothers and also servants of Oraclon's Japanese counterpart.