Ragaku (ラガクー Ragakū?) is the main antagonists from Kamen Rider: Armonsters who used to destroys the Gudo Tree and the fruits after the unknown human tribes attempt it. However, some of the Ragaku were not worked with the leader, so they went to their own goals, especially humans were partnered.
Ragaku has a life-cycle during the time of ancient.
RaEggs (ラ卵 RaTamago?) were slimy-like eggs as fully matured female Ragaku birth. It will hatched out the larval stage called Ragakii.
Ragakii (ラガキー Ragakī?) were larval Ragaku who hatched from the egg. Ragakii were apparently served as a footsoldiers. However, the Ragakii will be molts into the young version of the Ragaku called Ragakyu. Their footsoldiers were all unknown gender.
Ragakyu (ラガキュー Ragakyū?) were young version of the Ragakii who were molt from Ragakii's. Ragakyu were apparently served as a stronger footsoldiers. Unike Ragakii, they were male and female, but after they moult, they evolved into fully matured form, Ragaku.
GaiRakyu (ガイラキュー Gairakyū?) were alternate and male-only Ragakii were evolved into GaiRakyu, the adult Ragakii and incapable to evolve. GaiRakyu have female counterpart as the male Ragakyu's evolution called Ragakumi, but does only devolving when the full moon lights out.
When Ragakyu growns powerful enough, Ragakyu were moult and evolves into the fully matured form.
Ragakumi (ラガクーミ Ragakūmi?) were almost-nude female Ragaku which is allow to evolve when the full moon light on. After the evolution, her breasts were expanded, gaining their wings and change their appearances. When the full moon light goes out, they devolve into their normal forms.
When they not command by the leaders, they goes off to search the place peacefully before Agito shows up that Rouki learned he want to taste the Gudo Fruit too just like normal humans.
- Main article: Ragaku Warriors
|Kuraga Earth||Earth Demon Rouki|
|Kuraga Fire||Fire Demon Hidra|
|Kuraga Splash||Water Demon Medusa|
|Kuraga Wind||Air Demon Cyclous|
|Zorochi Shade||Skypes of the Orochi|
The Ragaku's main objection to destroy the Gudo Tree and the fruits before Agito and the others shows up.
- Rairai of the Golem
- Furei of the Firefly
- Kin of the Whale (absorbed by X and merge into Ragaku Beast himself)
- Byu of the Bee
- Zak-Ra of the Cobra
- Golehom of the Rock (1) - A rock Ragaku who used rocks to smash things. He was destroyed by Kuraga Earth's Claw Bringer.
- Kaiger of the Tiger (2) - A orange begal tiger Ragaku which is consumes human's energies to make them tired. He was almost defeated by Kuraga Earth's Leg Claw Kick, but assumes his true form before Dregcarrier arrival since Rouki's wish to bring out his personal Earth Mechanimal: Gorillana to destroys him with Banana Shooter.
- Daizu of the Stone (9) - A stone Ragaku who was Golehom's brother, controlling the rock to smash things and avenge his brother's death. As Daizu was beaten by Cyclous transformed state, he assumes his true form. However, the Dregcarrier send out her personal Wind Mechanimal: Dinochaser to brokes Daizu's core then destroyed by Kuraga Wind's Shooting Tornado.
- Blastin of the Tiger (5-6) - A crimson caspian tiger Ragaku who controls fire to burn down. As Agito and Medusa team-up and fight Blastin, Furei appeared and joined her to almost beat them unil Medusa transformed into her Ragakumi form when the full moon lights. After Furei and Blastin fled, she feels Agito's interest. When Blastin returned, Medusa assist Agito, allowing to transform into Kuraga Splash to destroyed her only assuming her true form. Dregcarrier arrived to Medusa that she wish to bring out her personal Water Mechanimal: Denkunagi and destroy her again with Electric Hydro Charge.
- Buju of the Zebra (8) - A dark-red striped zebra Ragaku who controls the fire to trapped them. With Buju was weakened by Medusa's transformed state, he assumes his true form when he consuming the fire. However, she used her Denkunagi to sprays him, turning into a statue then destroyed by Kuraga Fire's Twin Banishing.
- Durio of the Peacock - (11) - A red/green peacock Ragaku wielding the peacock feather-like sword. The peacock Ragaku gone berserk because using the Air power of Ragaku as does not count. Having Durio's rampage, Kuraga Earth managing used MeteoBurnter to destroys the berserk Ragaku.
- Belzer of the Salamander (3) - A bluish salamander Ragaku who controls the water to splash down the humans, trapping them into sphere. She was destroyed by Kuraga Earth's Leg Gorikick using Gorillana Bike Mode, consuming her by Rouki's Leg Claw Kick energy.
- Dokun of the Poison Frog (7) - A blue-purplist poison dart frog Ragaku who used poison on humans to stun them. He was destroyed by Kuraga Splash's Medusa Shot attack while riding with Denkunagi Bike Mode.
- Wamui of the Sponge (12) - A yellowish-blue sea-sponge Ragaku who controls the water creatures. As Medusa in transformed form poisoning Wamui with her Poison Cut, he assuming his true form to attempt to kill her but Dregcarrier shows up to destroys him with Denunagi Bike Mode then Medusa Strikyster.
- Mizaru of the Grasshopper (4) - A dark green grasshopper Ragaku when the stronger Ragakyu moults his own body who controls flying insects to lure the humans and trapped them into his cage. He is defeated by Kuraga Fire's Evil Banishing, but assuming his true form as before Dregcarrier send out his personal Fire Mechanimal: Phoenifiery to burnt into pieces with Fiery Burner.
- Abe of the Fly (10) - A fly-like woman Ragaku who controls flying insects to traps them into her cage. After Agito and Cyclous freeing the civilians, she was destroyed by Kuraga Wind's Eagle Thrust while Hidra cuting her wings off.
- Takin of the Pigeon (16) - A greenish-gray pigeon Ragaku who controls any birds.
- Ahu of the Armadillo (15) - A purple armadillo Ragaku who controls plants to trap humans. Kuraga and Zorochi team-up to battle against and destroys the Poison Ragaku without their partners by their Rider Kicks.
- X of the Star (13-14) - An Air/Fire combination Ragaku spawned by Durio's death. He used Air and Fire attacks to easily beat Kuraga Earth as well their other main forms. His powers was overwhelming Kin and absorbing him, so he merged him into one then mutates to Ragaku Beast. As Kuraga and D2 were defenseless, the mysterious Mechanimal named Orochiressha while encountering another Rider and bluish-black colored Ragaku helps two of them to defeat X by transforming into Kamen Rider Zorochi Shade and used Orochi Drop.
Ragaku Beasts (羅賀苦獣 Ragakujū?) were monsterous Ragaku who revealed their true forms causing wreck the cities.
- Both Ragaku and Ragaku Beasts were generally based on the animalia species.