The ninth volume of Tsukasa Fushimi’s Eromanga-sensei picks up from the last volume’s flashback to the past of the Izumi siblings and the huge development in the end.

Synopsis

“Long before I’ve met you for the first time… I love you.”

Confiding their past to each other, Masamune and Sagiri has finally joined their hearts together. In order to realize their new relationship, the two starts coming up with their children’s name, going to their first date, and having innocent exchanges. What do Elf and Muramasa say to those two!?

“It’s something I experienced a few days ago.”

Masamune and Kunimitsu are consulted by senior author Kusanagi about accidentally doing a dangerous mistake while drunk. Who is it that appears in his house? And what is the content of Kunimitsu Shidou’s new novel?

“I have to apologize to you siblings for something.”

Masamune reported his new relationship with Sagiri to their aunt, Kyouka. But Kyouka’s response is surprisingly… Kyouka’s complicated feelings behind her cold expression are—? The secret that Kyouka has been hiding from the Izumi siblings is finally going to be revealed!

I’ll be using pointers in talking about this to make it concise.

The volume picks up from the confession in the previous volume, where Masamune asks Sagiri to marry him. Masamune declares that he had planned to propose to Sagiri when their dreams finally come true. Sagiri is startled for a moment, but then tells Masamune that it’s too early for them to marry since she’s only 13.

Sagiri continues by confessing her feelings to Masamune and starts tearing up while thanking Masamune for his love towards her. Sagiri asks Masamune to go out with her and marry her someday, to which he agrees. Sagiri starts thinking about the way she’ll refer to Masamune from now on, but ultimately settles for “Masamune”. The story continues on to the days they spend together as lovers, from thinking about the name of their future children and making online orders together as a date. Specific references to To Aru Majutsu no Index (Accelerator) and Shakugan no Shana (Shana) are present.

While both Elf and Muramasa have expressed their best wishes for Masamune and Sagiri’s relationship, they don’t seem likely to give up on Masamune.

Senior author Ryuuki Kusanagi mistook a 20-year-old woman he flirted with a primary school aspiring light novel writer with the same name, Aya, and mistakenly sent a mail asking for burachira (lit. bra perving; yes, that word is a thing in Japan). It is now the job of Masamune and Shido to resolve the misunderstanding and restore Kusanagi’s social standing.

The misunderstanding is successfully resolved, but Aya ends up becoming Kusanagi’s disciple. Ryuuou no Oshigoto‘s front cover also makes an appearance in this specific scene and is used as sort of a metaphor for the scene. Another light novel that Aya brought in that scene is Ro-Kyu-Bu!.

Masamune and Sagiri announce their new relationship to Kyoka, but she doesn’t accept it. The reason’s related to Kyoka and their parents’s past; at that time, Masamune’s father and Sagiri’s mother were hesitant at first to marry, but were finally convinced after getting Kyoka’s encouragement. Kyoka herself believes this was what led to the accident that happened in their honeymoon. Kyoka told the siblings about the truth, thinking that it’s fine if they are going to hate her for this.

Kyoka attempts to leave the Izumi residence right after this, but the one who stopped her in her tracks is Sagiri. This scene is particularly meaningful since Sagiri has always had a hard time going out due to her trauma. The chapter concluded with the siblings forgiving Kyoka.

Masamune and Sagiri seems to be engaged by the epilogue, with Masamune consulting Megumi about giving an engagement ring and another present for Sagiri.

From the afterwords, it is mentioned that Dengeki Bunko will be releasing Ore no Imouto IF route light novel for Ayase, and Kuroneko’s route has already been planned.