Sereth is the true name of the store merchant that is found all throughout Falana in Dust: An Elysian Tail. The shadowed figure never reveals his identity in the game and remains in a cloak as a black silhouette with glowing eyes. He allows Dust to shop for different wares including armors, blade enhancements, necklaces, rings, food and materials.
Spoiler warning! This article contains plot details or the story in general. You have been warned.
Sereth is a Moonblood who follows Dust secretly during the entirety of the story, asked to watch over him by Elder Gray Eyes. He is a wise merchant who keeps away from the ongoing conflict, which allows him to move freely across the land. and remains safe from while supplying them for no charge. Near the end of the story, Elder Gray Eyes says Sereth was unintentionally followed by General Gaius' soldiers to Everdawn Basin. With this, the plan of surprising Gaius' army was backfired but still successful with the help of Dust. Dust can receive the first side-quest from Sereth, asking him to help out with stocking rare items for blueprints. Sereth also rewards Dust with a blueprint at the end of their first conversation together.
When Sereth is first met, he will activate a quest to sell him materials that are not categorized, whereupon Fidget will respond with, "Ah, he'll buy them at a high price," this is a reference to the Merchant from Resident Evil 4, as this is one of his most common lines in the game.