Vic is a trader whose route encompassed the Chosen One's village of Arroyo, where he sold them a flask that originated from the "holy" Vault 13. When the village requires a Garden of Eden Creation Kit in order to continue to survive, the player's first clue to the location of the Vault is the trader himself, hailing from a city to the east of Arroyo.
Vic is absent from the town, apparently having moved on to another city further east known as "The Den". Upon arrival, the Chosen One finds out that the poor sap has gotten himself into trouble with the slavers, and is not allowed to leave town until he fixes a broken radio he sold to the leader of the slavers. Should the player help Vic out and get him out of the slaver's residence, Vic happily admits he acquired the flask from Vault City, far to the east, from one of his connections.
He will offer to join up with the Chosen One, and brings to the table half-decent Small Arms capabilities and very good Repair skill.
Another small side-quest involving Vic entails bringing him to Valerie, a citizen of Vault City and, apparently, Vic's daughter. She chews him out for abandoning her and her mother while he was out trading with "tribals", and informing him that his wife and her mother had passed away while they were gone. There isn't much to gain from this altercation, though you obviously find out more about Vic and Valerie.