He's My Fiancée ! : I Went Back To The Past and You ! - Chapter 365 - 366: The Price-I

A typical, frail senior high school student had acquired the SuperCivilization Technology System. From academic dreg to academic prodigy, from the weak to the strong. Basketball genius, top-level hacker, medical sage, business tycoon... Empowering the nation through technology, elevating our great Huaxia!

In order to chase down and kill her own murderer, Xia Yichu reached an agreement with the 233 system, and she will travel through the world to complete the task, and The 233 system helped her return to the original world.
However, Xia Yichu often encountered a broken BOSS while he was on his way to do the task. He did n’t agree with each other on the wall, the bed, the various patterns, and kept talking.
System: Please use one word to describe the other person’s impression in your heart.
Xia Yichu: Competent.
Shen Jiaye: Mine.

- Description from 69shu

Follow Kairi Izumi—a quiet, eccentric, and somewhat conspicuous girl— who never felt like anything but an NPC in a story. Working behind the scenes, unnoticed by others had always been part of her daily life, dwelling with medicine and toxins.So, it's not surprising that she wasn't tad attractive according to others.That is, until one day... that guy, he confessed to me.Wait a minute—doesn't that mean I'm a heroine now? Hang on, how is that even possible? Me? Heroine? No way! I’m just a girl from a small village who likes to help others. I don’t particularly stand out, and compared to the other girls, I’m not even that attractive.And so, a question lingers, driving the unfolding of this dumbfounding narrative forward:Wait, what do you mean I got reincarnated to be a heroine?That's weird because usually a heroine is not strong let alone smart - they are usually dumb, cute and pretty. Definitely not me. I mean, how is that possible? Me? Heroine? No way!

A side story series featuring the girls of Kyoukai Senjou no Horizon.