Xanathar

The beholder who tried to use the psion girl Lena to make Neverwinter forget its ruler, intending to install himself as the city's lord. The spell went wrong and cast Neverwinter off the planet — out of memory itself. Lena fell ill; Xanathar retreated with her to a secret lair in the Greypeak Mountains east of Waterdeep. Months later Lena's brother Janus and Gambino found them; Janus banished Xanathar to that spot and took Lena away, hoping to heal her via Mordenkainen in Evereska. The New Leaves later entered Xanathar's hideout and fought his dream projections — finding him weakened, his visions having drained him. He surrendered, told them everything, and died.