The Elder Scrolls: Betrayal of the Second Era Valenwood Expansion brings the Sylvan province of Valenwood into the game, including a gazetteer booklet, new quests for all of the game's guilds, brand-new province-specific enemies, and province-specific delve and overland cards. This expansion also enriches every one of your BOTSE plays, regardless of if you're questing in the region, with new general enemies, items, classes (Arcanist, Burglar, and Ranger) and skill lines (Illusion, Legerdemain, and Light Armor). This expansion also includes a double-sided clash mat with new art that can provide a bit of extra theme when questing in forested or mushroom-infested locations.

All content can be seamlessly combined with the core box, with region-specific content being called for as required by quests and new general enemies, items, classes and skill lines able to be shuffled into the supply.