After surviving the brutal challenges of Idofront, Riko now possesses a White Whistle, allowing her to descend into the Abyss's sixth layer—The Capital of the Unreturned. Alongside Reg and Nanachi, Riko begins to explore the uncharted domain, where the ruins of the promised Golden City are located. As the trio starts to adapt to the harsh environment, they soon encounter dangerous creatures and treacherous landscapes. Their expedition leads them to a village inhabited by strange beings known as "hollows." Despite the creeping sense of unease that welcomes them, the three venture onward to uncover the mysteries of the settlement and long-lost legacies of the forgotten adventurers who once descended into the horrors of the unexplored Abyss.

OVAs bundled with the 17th, 19th, and 23rd tankoubon volumes of the Golden Kamuy manga.

Story of a girl born with a bad leg. Ritsuko longs to go to school and make lots of friends but it is not so easy. Her mother is very protective of her and at school she is teased by her classmates for her strange way of walking. Will she manage to keep her smile?

Sayonara Zetsubou Sensei OVA.