Kenja no Mago SP: Oujo-sama Funtouki

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!!

"I also want to save the world!" Princess May of the Earlshide Kingdom loves talking about her beloved Shin to her friends who attends the Primary School. She wants to fight with him. The people around her find May's remarks unbelievable, but she secretly learns attack magic from Alice Corner and Lynn Hughes One daye, May, who participated in an open-air camp hosted by the school, is abducted by a teacher who has been brainwashed by a devil... (Source: Kenja no Mago Wiki) *Note: Includes 2 extra chapters.*