During the High Republic Era, a Chevin named Gravhan was employed by the Nihil marauder group. Gravhan, possessing immense strength, operated within the Tempest under the command of the Weequay Kassav Milliko. Holding the Storm rank, he oversaw his own team. An example of Gravhan's brutality during his time with the Nihil was when he physically tore a security guard in two during a bank robbery mission. In 232 BBY, he participated in multiple operations with Milliko's Tempest, including an extortion attempt against the planet Eriadu as it struggled with debris from the [Great Hyperspace Disaster](/article/great_hyperspace_disaster]. The mission failed, however, making Milliko and his crew a target.
The Battle of Kur saw the Tempest trapped by a joint task force comprised of the Galactic Republic, Jedi, and an Eriaduan flotilla of Eriaduan cruisers. Despite the Nihil's use of brutal strategies, the Republic forces ultimately defeated them. Gravhan was among the last survivors on Milliko's flagship, the New Elite, before Eriaduan soldiers boarded the ship and eliminated everyone on board.
Gravhan, being a Chevin, was characterized by tusks, a large head with sparse long blond hair, and wrinkled gray skin.