Write a thrilling short story as a chapter of a crossover fanfic between Shinmai Maou no Testament/Testament of Sister New Devil, Nakaimo: My Sister is Among Them! and High School DxD  with plenty of dialogue and exposition, revolving around Shogo Mikadono, the future head of the Mikadono Group who attends Miryuin Private Academy under the name Issei Hyoudou to avoid his father's enemies. However, Shogo is actually Basara Tojo, a former child prodigy of the Hero Clan and the son of a legendary hero. Basara lost his memory after rescuing his half-sister, the reserved blue-haired girl Yuki Nodoka, from an ex-hero who had been possessed by the spirit of his [Basara/Shogo's] current sword Brynhildr as a young boy. 

Basara, who was mistaken for Shogo, was taken in by the Mikadono Group and raised as their heir. He later discovers his true identity as a member of a samurai association and reunites with his true father, the legendary rouge hero Jin Tojo. Despite keeping his true identity a secret, he has managed to reclaim his sword skills and Onmyōdō arts while pretending to be an idiotic pervert obsessed with women's breasts as Issei. The plot of this chapter would revolve around Issei being visited at his apartment by the silver-haired, sharp-tongued short-stack child prodigy Mei Sagara and the shy and reserved but also outgoing and loud redheaded President of Miryuin Private Academy's Economics Club, the bubbly Mana Tendou, who are upset about something.

Mei and Mana visit Basara because Mana is actually Millicent Gremory aka Mio Naruse, the daughter of  Sirzechs Lucifer, one of the Four Great Magical Kings of the Underworld, and Mei is infact her succubus bodyguard, Maria Naruse. Basara's true father, Jin Tojo had rescued them from a hit team sent by Sirzechs' enemies and had adopted them both as daughters. Mei/Maria confesses her love for Basara, along with Mana/Mio/Millicent and they all cuddle up together. Basara's younger sisters from the Mikadonos, the black-haired, green-eyed traditional Japanese beauty Konoe Tsuruma and the headstrong, feisty brunette Miyabi Kannagi, then arrive and also confess their love for him, and they all cuddle up together on the couch.

At the end of the chapter, Basara/Shogo and the girls are having a good time on the couch, but they don't know that Shinji Kanzaki, a former pilot of the EVA-Unit 01 combat mech under the name "Shinji Ikari", is watching them. Shinji is known as the "Black Sweeper" of Tokyo-3 for being a brutal underground vigilante whose main targets are small-time crooks and corrupt corporate executives. He [Shinji] is watching Basara/Shogo and his harem from a tree, taking notes and pictures of them. Shinji is not happy to see Mana/Mio/Millicent, Konoe and Maria/Mei showing off their large breasts to Basara/Shogo while rubbing themselves against his [Basara/Shogo's] body as Basara/Shogo and the girls enjoy each other's company on the couch. Shaking his head at this apparent display of idleness, Shinji leaps off the tree branch he was sitting on and lands on the group with a loud stomp, before teleporting to his nearby base to make his report.