The Lost Generation (空白の世代, Kūhaku no sedai) were a group lead by Akina Hiizumi's father with the other the members consisting of those from the same generation. While it was stated that they traveled to the Otherworld in order to stop the blooming of the Nanagou, in reality the members reside within the Zero-gou located in the Senate basement.
When Makiharu and Usuzumi attempted to enter the Zero-gou in place of their sons, they were stopped and incapacitated by their sons. Akina's father was the first to enter the Zero-gou. Over the next three years, members of the Lost Generation were chosen and allocated to their specific ports of the Zero-gou in a set order. Usuzumi's son was the seventh to enter, six months after the first in which time he had son, Murasaki.
Outside of the Senate and a few key individuals, others would be told that the group followed Akina's father to the Otherworld to investigate a way of preventing the merging of worlds. Their children grew up being raised by their community, resulting in them having very little memories or concerns about their actual parents.
- Akina Hiiuzmi's parents
- Kotoha Isone's parents
- Ao Nanami's parents
- Hime Yarizakura's parents
- Murasaki Iyo's parents