Vecna

Some manner of lich death god.

Has a lot of Left-Eye imagery associated with him.
Old and classic D&D villain apparently.

Also called the patron saint of secrets.

When talking about the Feywild: "At certain times certain doors open"... I wonder... we don't know where Vecna is... maybe Shadowfell? Similar thing happening there?
I need to look up who said that ^

Vecna was seemingly not considered a "god". They were just known as "very powerful"
It is said that Vecna wanted to become a god, but he was balked and scattered, supposedly destroyed a long time ago, but the cults still endure and infiltrate and wander various parts of Exandria .