The ESM - Elder Scrolls Master File is a game data file used by EDS-4, Oblivion and EDS-V Skyrim game modes. The ESM is developed for these type of role playing games. This file stores a multiplicity of different types of data, including 3-Dimensional meshes, video, music, sound, textures and more. Oblivion is the primary data file referenced by Elder Scrolls and is located in the Oblivion Data folder. Some modify ESM files in order to create custom game modifications, this can also be done using the ESP format which will allow the user to add plugins.