| Category | Ruins |
| Continent | Brucrumus |
| Region | Unaraggumak |
| Founded | Year 8702 DE |
| Map | Khelan |
Crulock is an ancient ruin dating to the time when the primordials and gods fought for control of Creation. In the Creation War, the Clans sector Narbuzad was a major theater of fighting. A primordial named Mephirouth came to Khelan, the Underdark sector beneath Narbuzad, and preyed upon supposed allies and foes. It is said that Mephirouth was more interested in perfecting and spreading diseases than helping the primordials or fighting the Nawirrûs Covenant. Mephirouth and his plague spewers founded Crulock as a base of operations. They built the walls and towers of the stronghold with rows of giant mushrooms and other fungal plants. The growth of these were accelerated and enlarged from exposure to magical globes. These Crulock Globes contain nature energy which has an amazing effect on the growth and health of Underdark vegetation and fungal creatures like myconids and yellow musk creepers. To prevent theft of these globes from his gardens, Mephirouth magically implanted virulent diseases inside them; that are still as potent and deadly as the day they were created over eight millennia ago.
Crulock is a very dangerous place to travel if you are not a gas spore, myconid, or other fungal-based creature. This is because many of the diseases that Mephirouth created or collected and brought to Crulock are still active. Diseases contracted here or brought out from the theft of vessels carrying them, like Crulock Globes, or fungal creatures that unknowingly serve as hosts, have had disastrous effects on surrounding populations. Thousands of kuo-toans perished in Wyzbrack from disease carrying myconids and those foolish enough to touch Crulock Globes sprinkled all around the area.
In the Horgon Era, Rioch Tetrax came to this ruin and advanced his study of disease. Like his tutor Mephirouth, he used a Cairn Scythe to maintain vitality while surrounded by deadly diseases.