Descent: Legends of the Dark – The Betrayer's WarExpansion

From BoardGameGeek:

Descent: Legends of the Dark – The Betrayer's War, a.k.a., Descent Act II, is a sprawling and deeply co-operative dungeon crawler driven by player choice – all powered by an app that allows for games to run without a Game Master. The game's immersive storyline is packed with twists and turns sure to thrill players of all skill levels. Campaigns can be played solo or with up to four players, requiring co-operation and skillful teamwork to overcome challenges. The Betrayer's War builds on the exhilarating dungeon-crawling adventure of its predecessor by introducing new villains, quests, and mechanisms. The game sees players returning to Terrinoth, where they find themselves in an unlikely alliance with their greatest enemy: Waiqar the Betrayer. They have to work together to battle against armies of dragons and the sinister machinations of the Uthuk Y'llan. All six heroes from the original game return to defend their legacy, each equipped with a new hero card and a variety of abilities to aid them in their battle against the impending darkness and the Dragonlord Levirax. -description from the publisher