Vecna is one of the most feared gods in the Dungeons & Dragons Greyhawk campaign setting (and, indeed, the entire multiverse), and his cult is always working in the shadows. As the evil god of secrets, Vecna seeks to rule over existence with his knowledge, destroying the other deities and anyone who opposes him in the process. The cult of Vecna is always working to ensure that their wicked god is victorious, which makes them great villains to use in a D&D campaign.
In D&D, Vecna is the god of secrets in the world of Oerth from the Greyhawk campaign settings. He was once a mortal king, who transformed into an undead lich, in order to accumulate limitless magical power. Vecna would eventually acquire a spark of divinity and ascend to godhood, with his power growing over the centuries. The name of Vecna is known all across the D&D multiverse, as his ambitious plots once put him into conflict with the Lady of Pain, one of the most powerful beings across all reality. It was unthinkable for anyone to oppose the Lady of Pain, yet Vecna did it and lived to tell the tale.
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Vecna is closely associated with the Greyhawk setting, but his prominent role in the D&D multiverse and its many planes means he can easily be slotted into one of the other D&D campaign settings with ease. The party isn't likely to fight Vecna himself, but his cultists are fair game, and they make for intriguing villains. The cult of Vecna operates from the shadows, use ancient secrets to destroy their foes, and has access to some of the most powerful magic items in D&D.
Vecna is one of the most despised deities on his homeworld, as even the other evil gods of Oerth would love to see
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