Rasetsu was the 24rth Haniwa Phantom to serve as Monster of the Week in Ep.21 of the Kotetsu Jeeg Anime: it was an avian type Phantom with a Red torso and pelvis, blue shoulder and leg joints, with a Green head and green scales in the arms, abdomen and legs, Yellow forearms and lower legs, purple beak, hands and feet.Besides flight, it had super strength, bright red shurikens located on its shoulders, and laser eye beams.

After berating her commanders, Himika comes up with a plan to trap Jeeg in a volcano, which is full of magnetism. She proceeds with her plan by unleashing Rasetsu, who confronts and defeats the MechaDon2 while the latter was doing training in the beach. Build Base sends Hiroshi and Michi to assist; Hiroshi transforms and builds up Jeeg for the fight. Despite throwing its Shurikens and avoiding Jeeg's Dynamite Punch, Rasetsu takes off and escapes, Jeeg following it with Mach Drills, it all the way to the Volcano Island to spring Himika's plan, avoiding Jeeg Beam and Spin Storm.

Over the crater, Rasetsu allows itself to be caught with Magnet Ropes and tries to drag Jeeg into the crater; Michi detects the magnetic waves emitting from the volcano, warning Jeeg. The robot breaks free, Rasetsu crashing into the crater bottom, while Jeeg and the Big Shooter retreat back to base, having avoided Himika's trap, the queen then comes up with a new plan to drag Jeeg into the volcano by using a hostage.

Not long after, Hiroshi and Michi take Dr. Ueda to the Airport, where he sees his wife and son, Jiro, to bid him farewell on his trip. After he departs, Jiro takes notice of Hiroshi's Jeeg necklace, asking about if he fights Phantoms with it, viewing it as a lucky charm. Later, Build Base receives a communication Signal from Himika's commander Amaso, announcing he has captured Dr. Ueda's plane with all its occupants, threatening to kill them is he doesn't show up at dawn, knowing his Jeeg's systems will go haywire. After talking with Ueda's wife and Son, Jiro prays to Hiroshi's necklace, begging Jeeg to save his father; Hiroshi takes heart to Jiro and decides to go to the island, not wanting to betray his trust. Michi and Hiroshi depart on the Big Shooter as his father warns him to be careful and conserve energy and suggest to use Mach Drills as a last resort, as perforating the rock might expose lava. They arrive on the island and Hiroshi jumps to transforms and build up Jeeg, landing on the bottom of the crater, finding the Airplane and Rasetsu; the two giants fight, but because of the surrounding magnetic field, Jeeg is weaken and the Phantom takes advantage. In that moment the Orochi fortress appears and blocks the crater, trapping Jeeg.

As Rasetsu punches and tosses Jeeg, a lava vein is expose putting the plane at risk; with circumstance now change, Jeeg calls for Michi who fires the Mach Drills, which rip through the volcano and connects with him (after using the Dynamite Punch). Jeeg tangles the Phantom with Magnetic Ropes and drags it out of the volcano, ripping through the Orochi from bottom to top. Now free from the magnetic field, Jeeg is able to fight in full force, the Orochi retreats with Jeeg going after it, Rasetsu tries to block its path and fire its laser beam, but Jeeg dispatches the Phantom quickly by ramming it at full speed. Michi tells Jeeg to leave the fortress and save Ueda and the Passenger.

Later, the passengers are reunited with the love ones, Jiro then asks Hiroshi to see the necklace so he can thank Jeeg, which he does, and the eye glow back at Jiro as a welcoming response.