It is shown that since Korone failed to seduce and manipulate Akuto, she is forced to resign as a surveillance agent. Hiroshi finds out that he is destined to become a future hero. Yukiko Miwa, Hiroshi's younger sister, goes to Akuto to verify if he is truly indeed a demon king. After both Akuto and Hiroshi deny their statuses, Yukiko runs off in tears. Hiroshi later explains that beneath the legendary lake is a shrine inside a cave, where a sword stands upon a rock. A mysterious man, known as Mr. X, awakens a sea cucumber beast emerged from the lake. Yukiko is captured by him, but Hiroshi and Kena try to fight back. However, Hiroshi is pummeled into the lake, while Kena is also captured in the process. Akuto and Junko rescue Yukiko and Kena, but Mr. X sends the beast to destroy the village on the island. While Akuto seems to be overwhelmed by Mr. X's attacks, Korone soon returns to stop Mr. X. Meanwhile, Hiroshi goes to the shrine where the sword lies. He is able to pull the sword out and gain the powers of a hero, deeming himself as Brave, and he uses a plasma-like attack to eradicate the beast. Korone is back to being Akuto's bodyguard, and she admits that she tries to seduce him in order to teach how to develop an intimate relationship with Junko.