Jason is Sierra's boyfriend.
Jason met Sierra while the two were at law school in America. The two became close and then started dating.
Then, after they both completed law school, they moved to the Island of Sodor together. When he found out about their relationship upon their arrival, Sierra's brother, Jacob was very disapproving of the relationship, later revealing that Jason had bullied him in elementary school. Jason later apologised for this, revealing that he only bullied Jacob because he was jealous that he had a family that loved him, as both of his parents had abused him as a child. The pair then made up and are now good friends.
Jason is a very reserved person. When he was younger, he was very rude and mean, but has since changed his behaviour and is now very kind and helpful.
- KnapfordFan23 partially suggested Jason's backstory.