Red Spear - S1.E16

While training in the mountains, Itsuki is attacked by a larva, a magical creature that makes nightmares reality, and is saved by Sekiren, a traveling member of Astral. On Itsuki's request, Sekiren trains him in martial arts. In a break in training, Sekiren visits Astral and asks Nekoyashiki to allow him to take on a mission offered to Astral. Kuroha takes tea to Itsuki, who claims that he is training so that others can rely on him. Magical pollution appears on the mountain, and Kuroha leaves to seek help, but after she and Honami return, Sekiren stops them. Meanwhile, Itsuki is attacked by the larva in the form of an armored soldier, and using Sekiren's training, is able to defeat it without using his Glamsight. Afterwards, Sekiren reveals he set up the conflict for Itsuki's benefit, and advises him to fight with his Glamsight rather than have it control him.