The Strongest Sage With The Weakest Crest Vol. 2 (Light Novel)

In Vol. 2, Mathias, who has obtained the strongest crest which has become known as the "Crest of Failure" due to the decline of magic and the misunderstanding of magical theories, senses a secret conspiracy by the demons. Together with his classmates Lurie, who holds the “Crest of Glory,” and Arma, who holds the “Crest of Standard,” he takes on the demons, and even the king and the dragons join in the fight too!
Notice: This book is written in Japanese.