Sent to an all-girls boarding school due to her father's overseas job, Sarah Crewe is a promising young girl who excels both academically and socially in her new life in London. However, her world is turned upside down when she is called into the headmistress' office and informed of news that no child wants to hear: her father has passed away. Now an orphan, Sarah is stripped of her status as a student and is forced to work in the boarding school as a maid in order to support herself. To make matters worse, her once friendly peers suddenly turn against her upon hearing about her fall from wealth. Coming to terms with the unfortunate situation she faces, Sarah must learn to persevere and form new friendships in order to regain her dignity as well as her identity. [Written by MAL Rewrite]

Momoko, who attends a special school, is both mentally and physically disabled. Every morning she becomes peevish because she can't go to the ordinary school with her twin brother Riki. Her family soothes Momoko by singing her favorite song "The Song of Frogs." One day, Momoko shouts encouragement to Riki who's playing dodgeball at an open classroom day and Riki's team wins the game. Ryuji, whose team lost the game, is not impressed and demands that Riki stop bringing his 'idiot sister' to school. Riki totally loses control and hits Ryuji with all his might. The following year, an experiment in integrated education is implemented and Momoko begins to attend Riki's school. Unfortunately, her physical condition takes a turn for the worse and she's sent to a hospital. Riki and all her classmates want to cheer her up and they set a goal of winning a relay race so that they would be able to tell Momoko the good news. Meanwhile, the fastest sprinter, Ryuichi, insists that he won't be taking part in the race.

Unaired anime episode bundled with the limited edition of High School DxD DX.1.

Nen: the hidden source of energy and potential that runs through everyone, and gives those that master it a source of great power. Inside Nen is the potential for limitless light and limitless darkness. The Hunter Association has arisen to control access to it. Hunters come in many shapes and forms, and with many different appetites - but all of them have learned to master Nen, and use it to chase wealth, power, and their dreams. The greatest and most powerful Hunter is Isaac Netero, chairman of the Hunter Association. Decades ago he sealed away Jed, a Hunter who had mastered the use of On, the dark "shadow" of Nen. Now On users have reappeared at the Heaven's Arena "Battle Olympia" tournament. For Netero, this is the last mission: to protect the Association and the world from a threat driven by hatred and the thirst for revenge. And he's going to need all the help he can get in order to succeed.