One-Eyed Fish (Episode 12)

One-Eyed Fish is the twelfth episode of the anime series.

Synopsis
This episode is effectively Ginko's origin story.

A Mushi Master named Nui comes across an injured boy in the forest and takes him in. We discover that the quiet, black-haired boy is named Yoki, and that he and his mother were lost crossing the mountainside when they were caught in a mudslide. Yoki wakes up after the mudslide covered in mud and debris. His leg is injured and beside him is the body of his mother, who had been killed by the mudslide.

Nui finds the boy collapsed from exhaustion in the forest, and takes him in.

Initially she is reserved towards Yoki, telling him "You can stay with me until your leg heals, but as soon as it does, I want you out". But over time Nui warms to Yoki, discovering that the boy has a natural ability to see mushi, a strong curiousity for the subject, and that he has no family now that his mother is gone.

The episode's title comes from the white, one-eyed fish in a pond near Nui's house. When Yoki asks what happened to the fishes' eyes, Nui explains that the mushi in the pond, feed on other mushi, generating a silver light. Repeated exposure to this light caused the fish to turn white and lose one eye. This light was also the cause of Nui's white hair and missing eye. Nui says she doesn't know the name of the mushi which cause the light, but she calls them "Ginko".

Yoki worries that further exposure to this light will make Nui lose her remaining eye, but she re-assures him, saying "Did you notice a single fish missing both eyes? No. This is the extent of the change." But we later discover that, when the Tokoyami eventually consume the fishes' remaining eye, the fish effectively disappears- a fate we see Nui succumb to, as well.

Nui also explains that she has spent the last six years in the mountains, looking for her husband and son, who she initially feared had their memories eaten by the Tokoyami. (She later reveals that her family were transformed into Tokoyami, and lived in the pond where she looked after them) She tells Yoki that, if you fall prey to the Tokoyami, you must keep one eye tightly closed to protect it, and cling to some specific memory, to avoid having your memories taken by the Tokoyami.

At the end of the episode we see Yoki wandering confused and exhausted in the forest. His hair is now white, his left eye missing and his remaining eye green, and his memories are gone, except for the word "Ginko", which he adopts as his name. He worries that his empty eye socket is attracting "strange creatures", which he takes as a sign that bad luck will follow him where ever he goes.