Season 1
In this world, young people who travel to another world (a fantasy realm) and return are known as “returnees” and often possess extraordinary powers. The protagonist, Akatsuki Ousawa, declined to remain in the fantasy world (Alayzard) after defeating the Demon King and instead returned to Earth — bringing with him the Demon King’s daughter, Miu Ousawa (who must pretend to be his sister). Back on Earth, they enroll in a special institution called BABEL Academy, which trains returnees who retain powers from other worlds.
Episodes
1. New Game Plus
Having vanquished the Demon Lord Garius, Akatsuki Ousawa bids farewell to the world of Alazyard and returns to his home world. His epic adventure has actually only just begun, though…
2. Bonds of Holy Water
Akatsuki and Miu attend their first day of school at BABEL. While Miu tries to fit in with her new environment, Akatsuki manages to get on everyone’s bad side.
3. To Become an Adult
Because of Akatsuki’s antics, the student council has threatened to send Kuzuha back to elementary school unless she spies on him. Meanwhile, Onizuka hatches a plan to get back at Akatsuki.
4. The Hero’s Back
Akatsuki uses his newfound sword to battle the powered-up Cockatrice. Meanwhile, Miu starts to come to terms with her father’s death and powerful COCOON members hold a secret meeting.
5. Just a Short Repose
Miu visits a shopping mall for the very first time to buy some new underwear. But hijinks ensue when Akatsuki gets a little more involved than he should…
6. Supersonic Sleipnir!
Akatsuki attempts to ride the fabled Sleipnir motorcycle. Meanwhile, terrorists strike in the heart of the city, and it’s up to the student council to stop them.
7. A Crude Panic on the Beach!
While Akatsuki and friends participate in a game of Beach Swimsuit Tag, powerful figures in Alayzard hatch a plan to find and retrieve Miu.
8. BABEL’s Ranking Matches Begin
As the school-wide ranking battles begin, all eyes are focused on Akatsuki and Miu. Even Kyoya and the student council are eager to show Akatsuki who’s boss!
9. On Such a Beautiful Moonlit Night
After the BABEL ranking matches are suddenly thrown into chaos, Phil Burnett arrives from Alayzard to retrieve Miu.
10. Where I Belong
In the fantasy world of Arezard, the rogue hero Akatsuki — at the request of the defeated Demon King — agrees to protect his fallen enemy’s daughter, Miu, and return with her to the world from which he came.
11. Before Daybreak
Having been outclassed by Akatsuki, Phil uses his trump card and transforms into a giant dragon! Akatsuki’s friends and the student council members struggle to buy time until Akatsuki can fully recover from Phil’s poison.
12. The World is Watching You
Akatsuki and Miu face off with Zahhak in a final battle. Meanwhile, the truth behind Phil is revealed in Alayzard and COCOON takes further notice of Akatsuki.