|Dates||???? – 2012 (killed by Castiel)|
|Location||Northern Indiana State Hospital|
|Episode(s)||7.17 The Born-Again Identity|
Marcus was an orderly working at Northern Indiana State Hospital's locked psychiatric ward, where Sam was held after he is diagnosed with suffering from a psychotic episode. Marcus became possessed by an unnamed demon who sought to harm Sam while he was vulnerable.
Marcus brings Sam food and asks how he is doing. He isn't allowed to give Sam much information about Marin when Sam asks, but does pass on that, unlike Sam, she isn't in the hospital because of an accident. Later, Marcus wheels Sam to a room and connects him to an electroshock therapy machine, at which point it is revealed that Marcus is possessed by a demon. He and a number of other demons have come to the mental hospital, having apparently learned that Sam is there in the midst of a mental breakdown. The demon possessing Marcus begins to torture Sam by electrocuting him on higher settings than the hospital would allow, planning to "cook" Sam's brains. He is in the middle of turning the power up even further when Castiel appears and smites him, saving Sam at the cost of the human Marcus' life.