Dnd 5e Eye Of Vecna. If a creature is attuned to a weaker eye they can replace the eye with a stronger eye. The Eye of Vecna and the Hand of Vecna are two of the most powerful magical items in the history of Dungeons Dragons so long as a character is willing to risk their soul in the process of using themIn the current edition of DD a character needs to attune to a magical item through a period of meditation and there is a strict limit to how many can be equipped.
Of Vecna all that remained were one hand and one eye grisly artifacts that still seek to work the Whispered Ones will in the world. Killing Vecnas worshipers destroying the lichs works and foiling his machinations all help to fulfill this goal. Originally from the World of Greyhawk campaign setting Vecna was described as a powerful wizard who became a lich.
When Vecna grew in power he appointed an evil and ruthless lieutenant Kas the Bloody Handed to act as his bodyguard and right hand.
Fortunately there is a roundabout way to handle this. The swords purpose is to bring ruin to Vecna. According to some Vecna had an obsession with acquiring and maintaining secrets believing them to be the source of true power. The swords obsession with those artifacts eventually becomes a fixation for its wielder.
