Ch'khalagu
The ch'khalagu were a type of demon in Romulan mythology. They were described by Elnor as "very bad demons".

In the story of Ganmadan, these demons were shackled at the beginning of time and were waiting for a call to release them from their bondage. This call came from Seb-Cheneb, who blew the horn of the hellbeast , after the death of her twin sister Seb-Natan. The coming of the ch'khalagu was announced by the sky cracking open. After their arrival, they would destroy worlds and lives in a period known as the Thousand Days of Pain. ()

Mythology
Romulan language