Mostyn (モスティン, Mosutin) is the first king of Talys, who united the island tribes. He is the father of Caeda and is friends with Lorenz of Grust. He hid Marth in Talys after his flight from Altea, and was rescued by him when pirates under Gazzak attacked the castle.
- Initially, he was not mentioned by name in any of the games, with his name coming only from supplementary materials.
- Though his name was long estabilished, it wasn't until Fire Emblem Warriors that his name was actually used in a game, with the DS remake Fire Emblem: Shadow Dragon reffering to him as Talys king.