Deities

Vecna

God of evil secrets

Pantheon
Greyhawk
Alignment
Neutral Evil
Domains
Knowledge, Arcana
Symbol
Hand with eye in the palm
Plane
Unknown
Worshipers
Necromancers, undead, those who keep or unearth secrets
Books
PHB p. 295, SCAG p. 125, XDMG p. 148