Epic Games, Inc., also known as Epic is an American video game development company based in Cary, North Carolina. In terms of Fortnite, they are the developers of the game, and its three gamemodes.
Prior to Fortnite, Epic Games was known for its Unreal Engine, a versatile game engine used for many popular games, such as Player Unknown's Battlegrounds and Rocket League, as well as the titular Unreal Tournament series of games. Epic Games were formerly known as Epic MegaGames. Before developing Fortnite, Epic was putting development staff into Paragon. Due to the success of Fortnite however, Paragon ceased development.
Sometime later, Epic Games launched their own store, from their existing Epic Games Launcher. This store allows customers to purchase exclusive games, as well as download others for free, or to play alongside existing platforms, such as Steam or Origin.