Manga adaptation of LN 7 of Mushoku Tensei

Princess Octavia was a high school girl until she was reincarnated into her beloved BL novel's world.
The fact that she's able to see her brother, the main character, and his lover so closely is a good thing, but both of them are male.
If so, won't there be trouble with future heirs?!
There's no way they'll make her take a political marriage to offer them a child, right?!
I don't want to be a character who's taken advantage of like that! If this is how it would be, I will surely find my own partner to be happy.....!!!

The manga is a romantic comedy starring the clever and handsome son of a wealthy family. In middle school he only ever studied, and everyone said he was plain like a background character. When he gets to high school, he enacts a plan to change his image to be more like a "main character" and get the perfect girlfriend.

The manga follows the everyday lives of five siblings—four sisters and one brother—who share a multi-unit apartment (danchi).

Echo-Pun is a 4-koma about Eiko and Haruka, two childhood friends who loved superheroes and pretended to be heroes while playing together. While in grade school, Eiko had to move away, but the two promised to meet up again in high school and become superheroes for real.

Haruka grows up into a normal girl, and upon entering high school, she suddenly meets her old friend Eiko. Eiko, however, is wearing a costume, fighting bullies, and calling herself Echo, a superhero. Haruka tries to keep Eiko out of trouble with both the bad guys and the disciplinary committee president, a girl named Kamikaze Shiori who, for some reason, seems quite interested in Eiko.

Can Haruka lead her old friend to the stable side of society, or will Echo drag Haruka further into the world of alter egos, costumes, and justice than she's ever gone before?