In 20 BBY, he was sent by the Sith Lord Count Dooku to observe General Grievous's experiments in turning Padawans into Force-sensitive cyborg warriors. He flew a Ginivex-class starfighter to Grievous's base on Belsus and expressed interest in the cyborg general's activities, even offering to assist Grievous in turning the younglings into cyborgs.
When the younglings escaped with the assistance of rebel Ugnaughts, Vulpus insisted on contacting Dooku immediately, and took offense to Grievous's threats, even standing up to the cyborg general's bandished lightsaber without flinching. He informed the angry general that killing him would bring down Dooku's wrath upon Grievous's head.
- General Grievous 3 (First appearance)