Vaughn is a plural entity born of mutual symbiosis: their main body, or "Host" (referred to from here on as Aughn), and their left arm, or "Symbiote" (referred to from here on as V).
Aughn was a rather large West Villager whom stood out for both their bulk and chitinous skin. They recall being chosen for their physical might and potential as a guardian for the Elders.
V was a small boy whom stood out for their ability to heal grievous wounds. His very flesh and blood could knit together the most devastating injuries, though came at great personal cost to them if they were not careful.
Neither have a good recollection of their past, though they distinctly recall V giving too much of themselves away, and Aughn refusing to let V die. Many of The Returned that Vaughn arrived with have some part of V in them, having given themself up for the survival of their crew. What remains of V is now integrated with Aughn's left arm, as well as various internals of their chest. Neither can survive without the other, and are slowly adjusting to their new life in good spirits. They seem to be the "parent" of the Returned Camp.