The Kappa is a summer-type Makamou with the feature of a snapping turtle and a frog. It is able to grow a new head to replace the one it discharges from its body, morphing into a copy. The Kappa ambushes Sabaki just finished off an its parents in Chichibu, defeating him easily. Hibiki prefers to fight Kappas on his own, due to personal reasons, assuming Kurenai mode to defeat the original and the copy it made. But another copy was formed at the last second and it attempted to escape from Hibiki in vain.
At first it places Hibiki at a disadvantage in the water due to gunk the Kappa shoots from its mouth, covering Hibiki's forearms and crystallizing. But Hibiki trained for such an event and managed to drive the Kappa out of the water to finish it off with his Shakunetsu Shinku no Kata, though chipping away at the hardened weights had side-effects for Hibiki's vocal cords.
During the start of Orochi, a pack of Kappa appeared at Higashichichibu, with the copies destroyed by Ibuki's Shippuu Issen while the original was to be killed by Todoroki's Raiden Gekishin, but was crushed by Otoroshi. A pair of Kappa emerge at Tatebayashi in 44, with one killed by Armed Hibiki'sKishin Kakusei, with the other killed by Ibuki's Shippuu Issen.
Kamen Rider Decade
Kappa appeared in Decade's series. he appeared in World of Hibiki and he defeated Kamen Rider Decade.
Kamen Rider Decade: All Riders vs. Dai-Shocker
The Kappa revived and join Dai-Shocker army.