MTL - Cosmic Trading System - Chapter 12 Last grievance

A mecha otaku is reincarnated into another world as Ernesti Echevalier (Eru). In this world there exist huge humanoid weapons known as Silhouette Knight. Dreaming of piloting those robots, Eru, with childhood friends, Archid Walter and Adeltrud Walter: together they will aim to become a Knight Runner, pilot of Silhoutte Knight.

I saved the Warrior who used to ignore and bully me and now she is obsessed with me.

Ji Qingzhou was anthropophobic and foolish. She had no redeeming qualities, except for her face.

Once she transmigrated, she was bound to a Guide System to save the world. She was tasked with capturing Shen Rongyu, the sinister, beautiful, mighty, gloomy villain and Great Shixiong of Xuanyun Sect, and to prevent him from destroying the immortal cultivation world in the future.

Can Ji Qingzhou, who had been single for 20 years, learn how to capture a villain?

Of course not.

She started off terribly, and muddled through the tasks that the system issued.

- Description from Novelupdates

Oosuki Masato is an ordinary high school boy who is magically transported to an alternative world, but for some reason his doting, over-protective mother comes along as well.