What is baelnorn?

Baelnorn is a type of undead creature in the Dungeons & Dragons fantasy role-playing game. They are powerful elven wizards or sorcerers who have achieved lich-like status through a magical ritual known as the Rite of the Arcane Transition. Unlike other liches, baelnorn are able to retain their sanity and their sense of purpose after death. They are also able to cast spells and use their magical abilities without relying on physical components or gestures. Baelnorn are often guardians of ancient elven tombs or libraries, and they are revered by other elves as protectors of their culture and history. They typically appear as spectral figures, surrounded by wispy robes or ethereal light. Baelnorn are immune to many physical attacks and can only be destroyed by powerful magic or by destroying the object or location that anchors their spirit to the mortal plane.