Atoko (also known as Atko) is an Atlach-Nachan. Her character design resembles Hatsune Hirasaka from the visual novel Atlach-Nacha; an outfit with a spider motif. (It is named after Clark Ashton Smith's creation Atlach-Nacha, the spider-god from the Cthulhu Mythos.) She has an appearance that is more mature than Nyaruko, Kūko and Hasuta, despite the fact that they are all around the same age.