Asumu

Asumu is the only student of the Ongekido Taiko Drum Style. Before inheriting Hibiki's powers, Asumu was able to assume a form similar to Transformed Kyosuke called Transformed Asumu. He is now the World of Hibiki's version of Kamen Rider Hibiki.

History
Asumu (アスム) is Hibiki's child apprentice, wanting to become a full-fledged Oni just like his master Hibiki in the taiko drum-based Hibiki Style of Ongekido.

Asumu is the only student of the Ongekido Taiko Drum Style. As a result of his master losing the ability to control his Oni powers, Asumu later inherits the power to become Kamen Rider Hibiki, and uses his new abilities to work together with Akira and Todoroki to ally their schools. Asumu later appears in the World of the Rider War after his reality is absorbed into it, being the only survivor of the attack of the Fangires led by Kamen Rider Saga thanks to Daiki.

After defeating Super Apollo Geist, the convergence of worlds is not stopped and the World of Hibiki and Asumu disappears. Following Decade's death, he is revived and reunited with his friends. He later helps revive Decade and then appears along with Wataru to aid Decade in the final battle with Super Shocker to repay Decade for saving his world, turning into Armed Hibiki thanks to Decade's K-Touch.

Forms
In this form, Hibiki is a purple demon. This is his basic form and the easiest form for him to reach. To become this form, Hibiki simply needs to tap his tuning fork against a solid surface, the vibrations from the fork causing his body to be engulfed in a fiery purple aura. Hibiki also gains a second "oni face" which is a crest that forms on his forehead. Unlike most Kamen Riders, Hibiki does not wear a suit, rather his demon form is his true form. Hibiki's second form, also known as Hibiki Kurenai (響鬼 紅 Hibiki Kurenai), was reached during the summer of training. It is exactly the same in appearance as his original form save for the fact that it is red instead of purple. Hibiki learned that he would be able to go beyond his basic form during the summer. At first he was unable to reach this form completely, only able to transform his arms when under attack. This greatly drained him and caused him to begin tougher training. The third and final form Hibiki was able to reach is known as Armed Hibiki (装甲（アームド）響鬼 Āmudo Hibiki). Unlike Kurenai Form that simply changes colors, the armor equipments here are much greater. To reach this form, Hibiki must use the Armed Saber, also serving as a weapon in this form. When initiating the call "Hibiki Sōkō!" (響鬼 装甲) then hits the button on the bottom of the Armed Saber, Hibiki automatically assumes Kurenai Form, then is wreathed in fire. Hibiki calls upon the power of the Disc Animals to fuse with him, each becoming armor for his form. Finally, his oni face is covered with a samurai like shield and his horns expand. Hibiki is able to destroy most lower-leveled Makamou with little to no effort in this form. Decade's Final Form Ride allows Hibiki to change into Hibiki Akanetaka (ヒビキアカネタカ (茜鷹) lit. "Hibiki Madder Hawk"), then when Decade activates the Hibiki Final Attack Ride Card, Hibiki Akanetaka transforms into the Hibiki Ongekiko (ヒビキオンゲキコ (音撃鼓)) to deliver the final blow.
 * -|Oni= Hibiki
 * Rider Height: 222cm
 * Rider Weight: 156kg
 * Ability PerimetersKamen_Rider_Hibiki_(A.R._World).jpg
 * Punching Power: 20 tons
 * Kicking Power: 40 tons
 * Max Jump Height: 75m
 * Maximum Running Speed: 100m/3s
 * -|Kurenai= Hibiki Kurenai
 * Rider Height: 222cmHibiki_Kurenai.png
 * Rider Weight: 156kg
 * Ability Perimeters
 * Punching Power: 30 tons
 * Kicking Power: 50 tons
 * Max Jump Height: 90m
 * Maximum Running Speed: 100m/2s
 * -|Armed= Armed Hibiki
 * Rider Height: 233cm
 * Rider Weight: 168kg
 * Ability PerimetersHibiki_Armed.png
 * Punching Power: 40 tons
 * Kicking Power: 80 tons
 * Maximum Jump Height: 100m
 * Maximum running speed: 100m/1s
 * -|Final Form Ride= Hibiki Akanetaka / Ongekiko  KRD-HibikiOngekiko.png

Trivia

 * Asumu is the only main Decade Rider who is not the original version of the Rider that he is the counterpart of, as his teacher served that role, being the AR version of the original Hibiki.
 * Asumu is one of the two 'child riders' from Kamen Rider Decade, with the other being Kiva's counterpart Wataru.