Stout is the "second" oldest and part of the first set of twins from Applejack and Fin Sharp. He appears in Grounded and Glorified. See stories below:

https://www.fimfiction.net/bookshelf/1294304/bright-future?order=latest

Part of the identical twins in this family, Stout and his brother Cider are the family tricksters and good friends with Cotton, Fallacy and Prism. As he's gotten older, his relationships with a lot of ponies have become complicated, and in spite of finding his cutiemark, he still doesn't quite understand himself. He's flippant, dismissive, and indecisive. Everything is a joke, so long as he can keep it that way. The life of the party to distract himself from questions plaguing his mind.