Zachariah first appears possessing this man under the name Mr. Adler to pose as Dean Winchester's boss at Sandover Bridge and Iron to get him back on track as the Righteous Man after he loses faith after his encounter with Alastair. Zachariah shows disdain at having to possess the man calling him a "smelly thing" but finding it necessary to interact with Dean. This indicates that Zachariah only took the man as a vessel very recently. Indeed, he may have taken his form for the first time just to interact with Dean and put him in the situation he did given his comments.
In Heaven, Zachariah appears in the form of his vessel though he tells Sam and Dean that this is actually the form they merely perceive him in since his true form is too much for their human minds.
In a final confrontation, Zachariah is killed by Dean stabbing an angel blade through his head and his vessel dies with him. The body of the vessel is last seen in the Green Room as Michael descends and disappears afterwards and is never seen again.
- Season 4
- Season 5