Ep. 1: Yuuri is flushed into a toilet and transported to a medieval fantasy world.
Yuuri Shibuya, a Japanese high school student with a strong sense of justice, intervenes when his former classmate Murata is bullied. The bullies dunk his head in a toilet, sucking him into another world. Waking in an unfamiliar area, Yuuri mistakes the medieval attire of locals for a theme park. Villagers attack him until Adalbert von Grantz rescues him and uses magic to unlock the local language within Yuuri's soul. Conrad Weller arrives, fights Adalbert, and drives him away. Conrad takes Yuuri to a small village where Gunter von Christ informs him that he is the new king of the Demon Kingdom. They proceed to the castle, introducing Yuuri to Wolfram von Bielefelt and Gwendal von Voltaire, Conrad's two half-brothers who look nothing alike.
Episodes
- Ep. 1 · Yuuri is flushed into a toilet and transported to a medieval fantasy world.
- Ep. 2 · Wolfram insults Yuuri's mother, leading to a duel over engagement that ends with Yuuri revealing magic.
- Ep. 3 · Yuuri Shibuya declares himself Demon King after a magical mishap leads to a coronation.
- Ep. 4 · Yuuri forms a baseball team while facing a looming human war in another world
- Ep. 5 · Yuuri and companions sail to Van da Via island seeking the demon sword Morgif.