DxD: Scion of Lucifuge - Chapter 300: The War Game Begins—Yukari’s Light Magic—Megumin, the Melee Mage

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.

Abandoned by Fate, but Chosen by Chaos.A world where magic reigns supreme and the mightiest wizards stand at the apex.A world where one’s mana affinity, if one even had it, determines one’s status in society, whether one could soar through the skies like a dragon or remain grounded, scraping by like rats or chickens.This was the world Hal Fennec was born into.Raised in the poverty of a border village, Hal had one wish: to give his mother a better life, one free from the constant fear of beast attacks and invasions by the Fellkin.But fate seemed to be playing a cruel joke.Despite being the brightest and most confident among his peers since childhood, Hal turned out to be barely qualified to become a wizard.His natural talent, contrary to his expectations, was nowhere near enough to fulfill even his modest dream of a decent city life.But then, just when his final hope was snuffed out and the future seemed gray and bleak, a twist of fate—or more fittingly Chaos—granted him a system that would turn everything around.

You Liangxing would never open the speech function in game.
That was because his voice was…
Particularly! Kittenish!

But there was one day, he queued up with a teammate who had so much to say that they may as well explode. Vexed to the point of no return, he contributed a voice that was capable of splitting heaven and earth, “Don’t BB.”
The other party who was being scolded stilled. In the ensuing silence, he suddenly let out a long, relishing… Moan.
You Liangxing: “…..”

Later —
He realised that the person was a great god,
Much later,
Without him realising,
He became the great god’s royal healer.
…. And also his boyfriend.

- Description from Novelupdates

Ethan accidentally rode the wrong train and ended up in Brynhildr Magical Academy where Wizards and Witches are taught on how to use Magic.As someone who didn't have any magic powers, he thought that he would be punished for being in a place where he wasn't supposed to be. Fortunately, due to a stroke of luck, the teenage boy managed to avoid the worst case scenario, and ended up staying in the Magic Academy to learn magic.Ridiculed by many for being magically crippled, Ethan strived to adapt to his new school life with the help of his new friends, who made him realize what True Magic was all about.