Seth was the camera man for the production of Marble Hornets. He was first named in Entry 5 and was first seen as the cameraman in Entry 9. He may have also been the one filming Entry 20. He is again seen as a member of the film team when he is caught in the rain along with Jay and Tim in Entry 54. Seth disappears during Entry 22, presumably taken by The Operator.
Seth appears to be an easy going and submissive individual. When Alex is yelling at Seth in Entry 9 for turning off the camera for a little while to conserve film, Seth takes the abuse while the cast members defend him. He is later seen teaming up with Alex to investigate the bath house in Entry 22, which leads to his supposed demise.
Some have theorized that Seth is totheark. This is largely due to him being the camera man. This presumes he would have access to footage that Jay would not have gotten from Alex. Personally i belive that he could well be totheark or at least involved with the channel of some sort. He was involved with Marble Hornets, was the cameraman meaning he has the camera skills to pull off the effects used in tothearks videos. He is also pretty low profile. Except for Sarah he has been featured the least out fo the crew for Marble Hornets. He was betrayed by Alex which gives him the motive to do try and get revenge on Alex. ~StoneFly