Isekai Maou to Shoukan Shoujo Dorei Majutsu - Volume 10 Chapter 5 part6

In this world, only if you are strong, can you protect the people you love.

She, a 21st century mercenary queen, had crossed over into a tragically betrayed body of a waste. Waste? She will show them what it means to be a waste! Betrayed? With the Ancient Manual in her hands, she will astonish all the despicable men and cheap women!

What the hell? That menace who bullied me since I was six years old, actually became a pretty girl after three years of living apart? And she even ran to our agreed duel location to confess to me, hoping that I can become her boyfriend?!

This is a plot against me! There’s definitely an enormous conspiracy behind this! I won’t be fooled by you! Even if you tear up and act all pitiful, I will still disregard you and humiliate you, until you’ve have completely paid back all my childhood grievances!

What’cha lookin’at? There are very reasonable grounds for bullying a girl!

- Description from Novelupdates

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.