Fate Bound in Chains
Vecna’s secrets are an interesting group. When a dark wizard gets powerful enough to attract Vecna’s attention he will approach them with an offer, an offer of power. IF the wizard accepts this offer then Vecna will have the wizard join him in a ritual, upon completion the wizard is destroyed and his essence is turned into a page that Vecna binds into his spell book. This page contains a spell that allows Vecna to summon and control the wizard whenever he feels like. Vecna of course keeps this all a closely guarded secret.