The Children of Ket-Cheleb were a militaristic group that was formed from a cadre of followers that served the warlord Sudoc. They were led by Tellus who despised the peaceful society that Surak would bring their world and planned to leave to continue their way of life on another planet. Surak attempted to convince them to stay on the homeworld but they would hear none of it and left in generation ships from the planet. This group would be part of the many Vulcans-in-exile that would form the Romulan culture.
Historians speculate that the Children of Ket-Cheleb had access to possible warp technology that was being developed by Sudoc's army with the prototype being taken by Tellus himself for his exodus from the mother world. (Last Unicorn RPG module: The Way of Kolinahr: The Vulcans)