Yomi

Kōhai Tochi (荒廃土地, Japanese for Blighted Land) is a spiritual realm home to some of the most wanted and violent criminals spanning the spiritual world. The realm was once abadoned after an incident involving the and has since become a nest of scum and villainy. The realm is large and expansive, with the single city being almost as large as the ; with a large amount of wasteland outside the expanse of the city.

Overview
The realm is accessed through the the deepest reaches of the Dangai, or by a three-month journey from by boat across the spiritual seas seperating the two realms. The sky is predominately dark and murky, a consequence of the incident that led to its abandonement centuries before.

Due to the effects of the Dangai seeping into the realm, it is impossible for one to release either the or  release of their  as such an action would cause them to be trapped by the Kōryū (拘流, Wresting Flow). releases - or ones of similar nature - are excempt, though why is currently unknown. Human powers, such as, Helix Daggers and can be used safely and without any drawbacks, however.

The City
The city is designed with the same manner as that of the 's, in that it appears to be constructed with a design similar to that of a Japanese Castle called a shiro, only it has no wall surrounding it. The buildings present appear in the fashion of feudal Japan, as they mostly look to be made of stone and wood, when in fact it is a weaker form of stone, as it does not guard against the forces of the Dangai, but it still prevents most other spiritual forces from breeching it.

The Warrens
The slums and generally the most poor and lawless areas of the various districts scattered throughout the city. Each Warren is home mostly to young children and adolescents who remain in small groups called guilds. Trash lines the streets, rats run wild and disease is writhe. The houses are cramped and large, some reaching five stories high and hold multiple families per single hovel.

Merchant's Quarter
A slight improvement over the Warrens though not by much. The houses are the same multi-story messes seen throughout Kōhai Tochi, though the bottom floor is generally made of cheap stone to add to the foundation of the wooden hovels built above. Here the merchant clans sell their various goods and wares, each having personal guards to prevent thievery from the children in the Warrens or from their rivals.

The Surrounding Wastelands
The wastelands are akin to the of the Soul Society in terms of size, but there the majority of the similarities end. This area is barren and mostly devoid of life with the exception of plants and small animals living in the ground or among the rocks. Anyone attempting to enter without prior knowledge through the Dangai end up coming out in the wastelands, which usually take in itself anything between one day or twenty to traverse, depending on your location.

Collective Vices

 * Main Article - Collective Vices.

The Collective Vices (集団悪徳, Shūdan Akutoku) use Kōhai Tochi as their base of operations, with almost every citizen of the spiritual realm being affiliated with the group in some shape or form. Though because power isn't held by a single individual, the citizens are split into factions that follow one particular member of the group. This often leads to turf wars throughout the city, mainly for control of trade routes into the city.

Averian's Faction
The faction that follows Averian are known to be very hard-line in their dealings with other factions and even its own members. They aren't above kidnapping important individuals to demand ransom from the nobles of, nor would they hesitate to murder woman or children. They also double as experienced assassins, known for taking on any job. While under the effects of his amnesia, Dastan Shiba was aligned with this faction.

Shadōkingu's Faction
Those who follow the Shadōkingu are known for being moderate, at least in comparison to Averian's crew. They are particularly well known for their dealings in the field of drugs, especially the potent and largely sought-after Reiyaku (霊薬, Spiritual Drug), due to its potency and profit. They are commonly branded with the Shirushi so the Shadōkingu can control them and prevent them betraying him. The Imawashī make up a large number of this faction, and are some of its most feared members.

Inai's Faction
The members under Inai Satonaka's rule are known to be quite secretive, even to the point of none of them being seen, though many have been named. They are collectively known as the Masukage, as they are almost ninja-esque, assassinating everyone and anyone who gets in their leader's way.

Sena's Faction
Sena Kyosai's faction consists mainly of rogue shinigami that seek revenge on someone who hurt them somehow or have crossed them. In his faction are also a number of humans, including Apollo Myberg, who betrayed his friends in Hama Town in order to gain greater strength and Asatoraru Kaigan who is a Fullbringer who seeks to destroy humanity in itself. It was thought that this faction was initially led by Shori Keihatsu, but it was just a ruse set in place while Sena left to recruit more people for his faction.

Sabishii Kunsha's Faction
Sabishii's faction consists of only Shinigami. All of which are rather mysterious but very powerful, nonetheless. His faction consists of three fighters, one female and two males. Because of the fact that a Zanpakutō's release can't be used in this world, all of the Shinigami in this faction are more powerful than the average fighter. Him and his faction act as a guards to rebel warriors whom have been captured. The prisoners captured inside here vary from human to demon, but all include people who would rather die than join the Vices. As for the prison, it is a large citadel that seems to be rather unguarded at times but is actually heavily protected and can be easy to enter, but nearly impossible to escape. It is protected by large stone beacon like towers which oversee most of Kōhai Tochi. All the while the stone their is made up of weaker Sekkiseki stone. He and his faction is proclaimed deceased following the destruction of the prison and rescue of Akiye.

Trivia

 * Kohai Tochi was created by a Lesser Tenjin called The Builder, the Twin Brother of The Engineer. Kohai Tochi was intended to be the Twin Realm of Heisekai, which was coincidentally created by The Engineer. However, Kohai Tochi was corrupted of its original purpose by The Outsider by allowing the to slowly seep into Kohai Tochi. Many of the native Souls eventually became lost to the Dangai's flow, allowing criminals and exiles from Soul Society to invade Kohai Tochi without much resistance.