|Appearances||Saw V, VI|
|Died In||Before Saw (chronologically); Saw V (flashback)|
|Cause of Death||Severed in half by The Pendulum Trap|
|Reason Tested||Killing the younger sister of Mark Hoffman|
|Relationships||Angelina Acomb (ex-girlfriend and murder victim, deceased) Mark Hoffman (killer and girlfriend's brother, deceased)|
|Portrayed by||Joris Jarsky|
|“||I did what I was supposed to do...||”|
— Seth's last words before his death
Five to six years before the events of "Saw", following a domestic dispute regarding her attending a going-away party for her co-worker, without inviting him, Seth flew into a violent, jealous rage and murdered Angelina in cold blood by slitting her throat. After being taken into police custody and found guilty of the murder, he was sent to prison, where he was to stay for the remainder of his life. However, due to an unspecified legal technicality, he was released after serving only five years.
One month after Seth's release, an enraged Hoffman kidnapped him and placed him in an Jigsaw-esque trap inside an abandoned building, in which he would have to crush his hands or a large, bladed pendulum would sever his torso. Seth initially denied that he killed Angelina and claiming that her death was an "accident", but did so, crushing both of his hands. Despite this, the trap killed him anyway, revealing it to be inescapable and designed to execute Seth while Hoffman watched through a peephole. This was subsequently blamed on Jigsaw. However, unbeknownst to Hoffman, the real Jigsaw, John Kramer, heard about this and tracked Hoffman down, ordering him to help him otherwise he would expose the truth. This led to a chain of events that led to Hoffman becoming John's successor as the second Jigsaw killer.
- Seth Baxter is responsible for the chain of events that led to Mark Hoffman's actions throughout the franchise.
- Even while inside a Jigsaw trap, Seth still never owned up to his actions or apologized for them, merely claiming that "[Angelina's death] was an accident". This means that Seth would likely not have changed even if he did survive the trap, making him one of the least moral characters in the series, along with Cecil Adams.