The Secret of the Pure Light is the one hundred eighth episode of the InuYasha anime.
- Kikyō meets a doctor named Suikotsu who is taking care of children in a village; she notices that he is dead, and has a shard of the Shikon no Tama in his neck, though she notes that the shard is completely pure, to her confusion.
- Inuyasha and his friends soon find them, and they immediately believe Suikotsu to be a member of the Shichinintai, though he has no recollection of what they are speaking about.
- Not long after Inuyasha arrives, the Shichinintai do appear, and instruct Suikotsu to join them once again.
- At first Suikotsu does not understand what they mean, but after Jakotsu slashes him with his blade, Suikotsu's whole persona changes and he grabs one of the children from the village by the throat, introducing himself as "Suikotsu, of the Band of Seven."
While Kikyō, intrigued, stay near Doctor Suikotsu to unravel the mystery of the purity of his Shikon shard, Inuyasha sits by a fire with his friends, swearing he will kill each and every one of the band of seven. When he meets Suikotsu, he pegs him at once as one of the seven, due to the characteristic graveyard scent, but his manners are so different from those expected of a murderous mercenary, young children make him a shield of their bodies. Miroku tells Inuyasha to desist, saying that maybe there is a mistake. Kagome is unsure, due to the purity of the shard. Farther away, the remaining members of the band of seven attack the village. Suikotsu rushes to the help of the villagers, joined by Kikyō. The band tells Suikotsu to "snap out of it", which he doesn't seem to understand, until Jakotsu hurts him, spilling blood over him. To the astonishment of Inuyasha, his friends and Kikyō, he then attacks the children, entirely transformed, and introduce himself as Suikotsu of the band of seven, seemingly with a personality disorder.