The mini-expansion introduces a climax to The Codex of the Infinite Planes Saga, where players must face the sinister presence of Vecna and his cult in Morgrave University. Vecna Unleashed offers new adventures in various locations, including Sharn, the Plane of Water, the Abyss, and the Astral Plane. Players will battle against new monsters such as humanoid rodent Wererats and abyssal demonic Vrocks, while also unlocking a new Epic Destiny called the Machrotechnic.