Kenja no Mago

Kenja no Mago (賢者の孫 lit. Magi's Grandson) is a Japanese novel series written by Yoshioka Tsuyoshi and illustrated by Kikuchi Seiji. Individual chapters have been serialized in Enterbrain since July 30 2015. The novel was later serialized as a fantasy manga illustrated by Ogata Shunsuke in the magazine Young Ace Up (Kadokawa). As of November 30, 2017 there are 5 volumes of novel and 1 volume for the manga.

Synopsis
A young man who had surely died in an accident, was reborn in another world as a baby! After that, he was picked up by the patriot hero "Sage" Merlin Wolford and was given the name Shin. He was raised as a grandson by Merlin and soaked up Merlin's teachings earning him some shocking power however, when he became 15 his grandfather Merlin said: "I forgot to teach him common sense"!

An "abnormal" boy's unconventional other world fantasy life starts here!!

(Source: Translated from official synopsis)

Trivia

 * Japanese Comic Ranked 21, April 24-30.
 * Japanese Comic Ranked 12, July 24-30.
 * Japanese Comic Ranked 10, October 23-29.
 * Kenja no Mago Fantasy Novels Get Anime.