Background and Early life
Based on a letter written by Seth which Abby Anderson finds in an abandoned cabin, Seth is a husband and father of three sons from San Francisco. During their quest to find Jackson, Seth's wife and oldest son were murdered and most of their supplies stolen outside of Reno. As detailed in his letter, Seth described that the heavy snowfall made it impossible to find Jackson and his two remaining sons were starving to death.
On a Wednesday, Seth and his sons decided to head out, west-northwest, across a ridge and towards gunshots they had heard in the distance. He eventually made it to Jackson and has lived in the community there for several years. He runs one of the local bars, helping cook food in the kitchen.
Events of The Last of Us Part II
On the evening of the winter dance, Seth catches Dina and Ellie kissing on the dance floor and asks them to stop, as there are children present. Though Dina consents, Seth calls her a homophobic slur, causing Ellie to confront him, which leads to Joel pushing Seth in Ellie's defense. Maria and Tommy stop the altercation and take Seth outside to speak with him.
The next day, Maria makes Seth apologize to Ellie in the local bar. He claims that he was drunk and didn't mean what he said. To help show that he was sorry, Seth made steak sandwiches for her. When Ellie is reluctant to accept them, Maria does so on her behalf. Seth wishes her good luck before returning to the pub's kitchen.
Ellie, not convinced of his apology, gives the sandwiches to Jesse instead, citing she doesn't want something from a "bigot".