Wise Man's Grandchild x Male Reader

I own nothing. Only the changes in the story and the name maybe? Other than that, nothing here is mine, just a fanfiction.

Everything and I mean everything about this book is subject to changes. The reason? Simple. Because this book is normally a one-love book. Basically, I know some people would prefer harem to one-love, so that is hard to adjust, second, plot differences, third, everything about it might have to change while keeping the same storyline.

Anyway, here is the description:

A young salaryman who died in an accident was reborn in another world filled with magic and demons.
As a baby, he was picked up by the patriot hero "Sage" Merlin Wolford and was given the name Yuu.
He was raised as a grandson and soaked up Merlin's teachings, earning him some irresistible powers. However, when Shin became 15, Merlin realised:
"I forgot to teach him common sense!"
Diseum, king of the Earlshide Kingdom, recommends Shin to attend his Magic Academy, on the agreement of not using Shin for political warfare.
In the capital, Shin rescues two girls, Maria and Sizilien, from thugs, and later he would inaugurate a club that consist of him and others.
Follow Yuu and his friends adventures while seeing Yuu try to live with no common sense at all packed with stupidly overpowered abilities while also to finish it, being incredibly intelligent in everything (apart from common sense of course)