The Offense and Defense Assasin! Shun's Secret Chain! - S1.E79

Koga, Yuna, and Souma advance through the first path while Shun stays behind to deal with the enemy reinforcements. However, the Secondary Pallasite Surtr blocks their path enveloped in a defensive barrier that seems impenetrable, until Shun catches up with them and realizes the secret behind the enemy's trick.