The Strongest Sage with the Weakest Crest 18 (manga)

A chaos demon with greater power than Zaridias will soon be revived. Such a powerful demon is beyond what Matthias and his friends can handle, but an ancient sword may be able to give them a chance. However, the ancient weapon is sealed in a casket that is guarded by an incredibly powerful elite demon and in order to obtain the weapon, Matty must use himself as bait to distract the demon!