Tsathoggua is not ambitious. He does not seek worshippers, does not extend his influence, does not broadcast dreams or manipulate the waking world from a sunken city. He sleeps in the lightless gulf of N'kai beneath the Earth's crust, and when the rites are correctly performed he accepts what is offered, and when they are not he continues to sleep. He has been patient for a very long time.

Patience, in his case, should not be mistaken for safety.

The Bureau classifies Tsathoggua at the highest threat tier despite his dormancy because dormancy is a behavior, not a constraint. Cthulhu is asleep because the stars are not right. Tsathoggua is asleep because nothing has woken him up. The distinction matters. The first condition is geological. The second is procedural, and procedures can be performed.

The Shape

Bat-furred. Toad-like. Vast in a way the Hyperborean texts describe with unusual specificity — Eibon gives measurements in cubits, and the cubits add up to something the size of a small temple. Slothful in the clinical sense: movement is metabolically expensive for an entity of his mass and origin, and he does not spend willingly. When the old Hyperborean accounts describe him as "indolent" they are not being insulting. They are filing a threat assessment. An indolent god is a god who has not yet been provoked.

The eyes are described, in every surviving source that mentions them, as half-open. Not closed. Half-open. Tsathoggua is not unconscious. He is waiting.

N'kai

The sunless gulf. A cavity in the Earth's deep geology that predates plate tectonics as the modern sciences understand them — older than the continents, older than the oceans, possibly older than the crust. Accessible, barely, through shafts in the Australian outback and under the polar ice and in two other locations the Bureau will not document in this file. The Voormis reached him there, provided for him, and received his blessing in exchange. The arrangement continued through the Hyperborean era and ended when the ice sealed the surface shafts.

The Australian shaft was rediscovered in 1932 by an expedition that did not return. The official report describes equipment failure. The unofficial report, which exists in two copies, describes something else.

Eibon's Rites

The Book of Eibon contains the cleanest documented account of Tsathoggua's worship. Eibon of Mhu Thulan was his high priest, his correspondent, and — before the end of Hyperborea — his only remaining access point to the surface world. The rites Eibon recorded are functional. They are written in the practical register of a working manual: ingredients, sequences, timings, contraindications. They were tested. They worked. The Bureau's position is that they still work and that nobody should test this position.

The ingredient list is largely available. The sequence is the difficulty. Eibon was deliberate about omitting one of the seven steps in every surviving copy, but the omitted step is different in different copies, and a determined researcher with access to three or more versions could reconstruct the full sequence. The Bureau is aware of at least D̵̳͝P̊F̷̀X̨̔ꫂY̊̔Ă͢͝𓆗ꙮŢ̳̄T̢̮̅ confirmed reconstructions in the modern era.

Threat Assessment

Classification Extreme despite dormancy. Tsathoggua is slow. Slow does not mean safe.

The current assessment is that he is hungry, has been hungry for roughly twelve thousand years, and will respond to correctly-performed rites with a precision that his apparent dormancy does not suggest. Every cult that has attempted contact in the modern era has succeeded in establishing it. The contact protocol is robust. What varies is the survival rate of the contacting party, and the survival rate trends asymptotically toward zero the longer the rite is sustained.

The single most important fact in this file: Tsathoggua does not need to wake up to feed. He needs only to extend. The extension is local, brief, and cleanly bounded. The bounded zone is generally a single room. Anyone in that room when the extension occurs is consumed. The room is left intact. The walls are sometimes faintly warm.

He returns to sleep immediately afterward and does not appear to remember the meal. This is not reassuring. This is the behavior of an apex predator who does not need to remember individual meals.