The Underworld

Yomi (黄泉) is the shadow-realm of Yomi no Sho’s cosmology — a parallel plane where the souls of the dead persist, diminished but aware, until they are either forgotten by the living world or called into service by a Warder. It is not a single place but a layered one, and the geography of Yomi is the geography of memory: zones correspond to the ways the dead are remembered, and they shift as the living world’s relationship with death changes.

This page describes the cosmology of Yomi at a high level. For specifics on individual zones, see Realms of Yomi. For the beings who rule over it, see Pantheon.

The Three Premises

Yomi operates on three metaphysical premises that are stated explicitly in the game’s opening cinematic and revisited throughout the lore. Understanding these is essential to understanding anything else about the world.

The Premise of Persistence. Death in the mortal world does not end a soul; it relocates it. A soul that crosses into Yomi retains its memories, its personality, and — crucially — its capacity for growth. The dead are not echoes; they are continuations. This is why Shades can be summoned, levelled, and Ascended: they are not beings of static power but living minds in a different state.

The Premise of Diminution. Persistence is not preservation. A soul in Yomi is diminished relative to its living form. Memories fade, skills atrophy, and the sense of self becomes porous. The rate of diminution varies — a soul actively invoked by a Warder diminishes far more slowly than one left to drift — but no soul is immune. The longest-tenured Shades in a Warder’s roster often have the most fragmentary memories of their living lives.

The Premise of Naming. A soul’s continued coherence depends on its name being spoken in the living world. This is the metaphysical anchor that prevents total dissolution. The Yomi no Sho — the eponymous Book of the Underworld — is, in this sense, a catalogue of names: a written record that keeps the dead tethered. The Warder’s role is to read the book, to speak the names, and in doing so to keep their Shades whole.

These three premises are why the game’s central activity — summoning, levelling, and deploying Shades — is also its central narrative act. Every mechanical interaction is, in-fiction, an act of remembrance.

The structure of Yomi

Yomi is layered, with each layer corresponding to a different “mode” of death. The layers, from outermost to innermost, are:

The Banks of Sanzu. The arrival zone. Souls cross the river Sanzu and arrive here, disoriented and unnamed. The Banks are the only part of Yomi that the living world can reach directly — it is where the Warder initially manifests.
The Field of Tethered Bones. The zone of those who died with unfinished business. Souls here are agitated, repeating the patterns of their final moments. The zone is dominated by the skeletal remains of those who could not let go.
The Hollow Shrine. The zone of those who died in service to a god. The shrine is vast and quiet; its souls are at peace in a way that the other zones’ souls are not. It is also the only zone where the pantheon’s influence is direct.
The Drowning Marsh. The zone of those who died by water. The marsh is suffocating and labyrinthine; its souls are confused and often hostile. Navigation is difficult and the encounters are among the most dangerous in tier 2.
Mount Kagura. The zone of those who died in celebration — dancers, musicians, festival-goers caught in disasters. The zone is paradoxically joyful and lethal. Its souls retain a strange clarity that other zones’ souls lack.
The Frozen Peak. The zone of those who died of cold or exposure. The peak is silent and slow. Its souls move at half the speed of souls in other zones, which is mechanically reflected in their high defensive stats.
The Sunless Throne. The innermost zone, where the dead who have been entirely forgotten by the living world drift. It is the domain of the Unmade, the final boss of the current endgame.

Each zone is reachable from the Banks, but the paths between them are not symmetric. The Hall of Eight Pillars, where Ascension is performed, sits at the centre of the map and is the only zone reachable from every other zone without transit through an intermediate.

The river Sanzu

The river Sanzu is the boundary between the living world and Yomi. Souls cross it once, on death, and cannot cross back. The ferryman — Sanzu-no-Onna in the lore, though she is referred to only as “the Ferryman” in the game’s UI — demands a coin for passage. Souls without a coin cannot cross and remain on the banks indefinitely, becoming Wandering Hollows (the lowest-tier enemy in the game).

The coin is not merely a toll; it is the soul’s last material possession, given to them by the living at their funeral. A soul without a coin is, in the metaphysics of Yomi, a soul that the living did not properly mourn. This is why Wandering Hollows are the most common enemy in the early zones — the modern mortal world has grown careless with its funerary rites, and the Banks are crowded with the unmourned.

The player character arrives at the Banks without a coin, having died in unusual circumstances that the game’s plot slowly reveals. The Scribe’s bargain — service as a Warder in exchange for retaining memory — is, in essence, the player character paying their passage through labour rather than coin.

The role of the Warder

A Warder is a living soul who has been granted the right to enter Yomi while still alive, in exchange for a binding obligation to maintain the Book. Warders are rare; at any given time there are fewer than a dozen in the world. The Scribe is one; the player character becomes another.

The Warder’s role has three components, each reflected in gameplay:

Reading the Book. The Warder speaks the names of the dead, which slows their diminution. In-game, this is the act of summoning and deploying a Shade.
Walking the Zones. The Warder enters Yomi to confront threats that the dead cannot face alone. This is the zone-clearing gameplay loop.
Binding the Unmade. When a soul has been entirely forgotten, it begins to dissolve into raw metaphysical material — the Unmade. The Warder’s final duty is to bind the Unmade before they destabilise Yomi’s structure. This is the endgame boss content.

The Warder is not, in the lore, a warrior. They are a custodian. Combat in Yomi no Sho is delegated to the Warder’s bound Shades; the Warder themselves never appears on the battlefield. This is why the game’s combat UI shows only the Shades and never the player character — the player is the unseen hand that holds the Book.

The metaphysics of summoning

When a Warder summons a Shade, they speak the Shade’s name from the Book and offer a Binding Slip — a small paper talisman that represents a fragment of the Warder’s own vitality. The Shade manifests in Yomi, briefly material, and agrees to serve.

The contract is not coerced. A Shade can refuse a summon, though this is rare in practice because service slows their diminution — a Shade that serves regularly retains their memories far longer than one that does not. The relationship is symbiotic: the Warder gains a fighter, the Shade gains persistence.

This is also why dismissing a Shade is not a trivial act. To dismiss a Shade is to stop speaking their name, which accelerates their diminution. The game does not portray this in detail, but the lore is explicit: dismissed Shades drift toward the Sunless Throne and eventual Unmaking. Players who dismiss Kagaribi (see the First Steps warning) are, in-fiction, condemning her to a slow dissolution.