Kenja no Mago
A young man is reborn in another world where he is adopted as a baby by the hero Merlin Wolford and named Shin. By his 15th birthday, Shin has accumulated all kinds of power by studying under Merlin, but one thing his adoptive grandfather didn't give him was a lick of common sense.
(Source: Anime News Network)
Episode 1 - A Babe in the Woods Goes to the Capital
Episode 2 - The Unconventional New Student
Episode 3 - An Emergency Arises!
Episode 4 - The Name of the Instigator
Episode 5 - A Pioneering New Hero
Episode 6 - Outbreak of War and a Joint Training Exercise
Episode 7 - Let's Go to Camp!
Episode 8 - A Starlit Pledge
Episode 9 - The Grandchild, the Magic Gear, and the Engagement Party
Episode 10 - The Fall of the Empire
Episode 11 - The Mightiest Corps of Magicians Ever
Episode 12 - And So, Off into the World...