Acchipecchi is a monster soldier belonging to the Monster Alien Soldier Corps, specifically identified as a Kaijin Issei Butai, in the series. This character was created by Gedorian from a man-eating cactus native to the Monster Realm. Acchipecchi possesses several notable abilities, including a certain degree of regenerative power and the capacity to transform into an ordinary cactus. For offensive purposes, this creature can fire the thorns covering its body as projectiles. A primary ability involves using these thorns to stab humans, which then transforms the victims into violent cactus humans, though this power is noted to be incomplete and not fully reliable. Additionally, Acchipecchi can use vines to drain life energy from others.

Upon its creation, General Jark declared Acchipecchi a failed experiment. Following this judgment, a plan was devised by Maribaron to power up the creature. This scheme involved Acchipecchi absorbing a young girl named Koizumi Chigusa, who had a great fondness for cacti. However, this plan ultimately failed because Chigusa was already acquainted with Minami Kotaro, the protagonist. This connection led to a confrontation with Kamen Rider BLACK RX, during which Acchipecchi was destroyed by the Revol Crash finishing move. The character's motivations and actions are primarily driven by the orders of superior officers like Maribaron and General Jark, serving as an antagonist force seeking to increase its own power through the absorption of an innocent human. The key relationship for Acchipecchi is with Maribaron, who leads the plan for its empowerment, and its target, Chigusa, whose connection to the hero directly causes its downfall.