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This article is about a/an episode in Madan Senki Ryukendo.

The Demon Hidden in the Water (水にひそむ魔 Mizu ni Hisomu Ma?) is the eighth episode of Madan Senki Ryukendo. It features the debut of Aqua Shark.


The river flowing through the town suddenly gets dirty, and the demon beast, Edenoid appears from the water! Pollution spreads in a moment. RyuKenDo and RyuGunOu are fighting the demon, but it escapes too quickly and lost track. S.H.O.T's member, Rin Sakyo, burns hostility at the demon who soils clean water as an act that cannot be forgiven. Rin had memories of her late brother. With her brother trying to protect the river where fireflies can live, Rin headed towards the forest alone for the search where Edenoid is likely to be lurking.


A pair of siblings are seen holding hands, standing near a river whereby the younger sister is looking at her elder brother with fireflies flying in the background. Rin is revealed to be the younger sister where she is thinking about why she doesn't understand back then. If nothing were done, she would have lost it.

Rin and Kenji are seen in Suijin forest with Rin holding her S.H.O.T. Phone to detect for demon signals. They are tasked by Setoyama to check it out as he detect a reaction earlier. Kenji asked Rin if Suijin forest has some significance to her as she comes out to investigate. Rin replies that Suijin forest resembles the forest back in the countryside and she hears that fireflies migrate here in the summer which is the same in countryside. Later, Rin is seen on the phone call with her mom where she is recalling the past of her elder brother in a protest to gain supporters to help to save the fireflies.

The next day, a group of children is seen catching crabs with Gajiro on a lake. Suddenly, they observe that upper stream water is polluted in red and steaming. Rin shouted at them to leave the lake immediately. Gajiro is late to leave the lake and gets electrocuted as a result. Demon Beast Edenoid appears from the lake and started to chase after the children. Rin lost the demon's signal upon the arrival of Kenji and Fudou. However, they notice Edenoid after hearing the cries of children nearby. They transforms and started to fight the demon. Edenoid spits acid at the Madan Warriors as it tries to flee. Edenoid manages to escape with incredible speed and jumps into the water. Back in S.H.O.T.'s Base, Setoyama is unable to locate the demon as it is not shown on demon radar. He deduces that Edenoid might be able to avoid demon radar detection by staying in the water.

Fudou is seen patrolling the streets for the whereabouts of Edenoid. He hears a scream suddenly and went to look into the matter. He saw a lady lying down and approaches her. The lady wakes up and clings onto Fudou. In another location, Edenoid is seen polluting the water, causing the people nearby to release minus energy. In Jamanga's Base, Doctor Worm is pleased with the work of Edenoid. As water is the source of life, losing the water will cause the people to fear more. In S.H.O.T.'s Base, Kenji sees that Rin is so uptight on the polluted water incident and drags her to eat. They visited the Croquette shop owner for a meal. Rin is amazed at the shop owner wife on her skill to fry the Croquette. She replied that it is not a skill, just put in a little oil, ensure the temperature doesn't drop. This gives Rin a hint and she went to do some research in S.H.O.T.'s Base and manages to locate the demon. It reveals that the next location Edenoid is going to is Suijin forest.

The next day, Rin is seen patrolling Suijin forest again and manages to detect demon signal via her S.H.O.T. Phone. She saw the demon and tries to move closer. She lost the sight of the demon suddenly and it reveals that Edenoid is behind her back. Rin tries to flee but Edenoid manages to stop her. While running, Rin trips and fall, allowing Edenoid appears in front of her again. She suddenly hears someone calling for her and she saw that the figure calling for her reveals to be her older brother. However, Rin seems to be hallucinating and the figure reveals to be Kenji. Kenji asked Rin to flee and transform into RyuKenDo to fight the demon. During the fight, RyuKenDo changes into Aqua RyuKenDo and manages to deal some damage to Edenoid. Aqua RyuKenDo uses its freezing ability to freeze the lake to stop Edenoid from escaping in water. Edenoid decides to escape using its incredible speed.

GekiRyuKen advises Aqua RyuKenDo to summon JuuOh. Using Shark Key, Aqua RyuKenDo calls upon Aqua Shark. Aqua Shark transforms into Aqua Boat, allowing Aqua RyuKenDo to get on it. Aqua RyuKenDo resumes his pursue on Edenoid, activates his finishing move, Freezing Slash to defeat Edenoid, obtaining a Madan Key as a result. In the night time, Rin asked Kenji how he figures the whereabouts of her. He replied it's based on instinct. Kenji asked Rin why did she call him Older Brother earlier. She replied that it was what she saw earlier at that moment. Rin thanks Kenji for protecting her earlier. They also manage to see fireflies in Suijin forest. In a housing apartment, Fudou seems to chat with the lady that fainted earlier. She thanks Kappa for granting her wish to meet a handsome man which is Fudou.


  • Kenji Narukami (鳴神 剣二 Narukami Kenji?): Shogo Yamaguchi (山口 翔悟 Yamaguchi Shogo?)
  • GekiRyuKen (ゲキリュウケン Gekiryūken?, Voice): Kenji Nojima (野島 健児 Nojima Kenji?)
  • Juushirou Fudou (不動 銃四郎 Fudō Jūshirō?): Gen ( Gen?)
  • GouRyuGun (ゴウリュウガン Gōryūgan?, Voice): Yasunori Masutani (増谷 康紀 Masutani Yasunori?)
  • Rin Sakyo (左京 鈴 Sakyō Rin?): Kumi Imura (井村 空美 Imura Kumi?)
  • Yuuya Amachi (天地 裕也 Amachi Yūya?): Kei Shimizu (清水 圭 Shimizu Kei?)
  • Kiichi Setoyama (瀬戸山 喜一 Setoyama Kiichi?): Kentarou Miyagi (宮城 健太郎 Miyagi Kentaro?)
  • Gajiro (ガジロー Gajirō?): Ryota Sato (佐藤 亮太 Sato Ryota?)
  • Doctor Worm (Dr.ウォーム Dokutā Wōmu?): Takao Handa (飯田 孝男 Handa Takao?)
  • Kumazo Inomata (猪俣 熊蔵 Inomata Kumazo?): Daisuke Iijima (饭岛 大介 Iijima Daisuke?)
  • Kuniko Inomata (猪俣 邦子 Inomata Kuniko?): Chige Tominaga (须永 千重 Tominaga Chige?)

Arsenal Used


  • to be added

Today's S.H.O.T. Information

Featuring Aqua RyuKenDo's JuuOh: Aqua Shark

  • Aqua RyuKenDo can summon the obedient and smart mecha support animal. When he transforms, he becomes Aqua Boat which can reach mach speeds.