Xanathar

the Xanathar was one of most infamous Beholder of the Realms and the crime lord of the Xanathar Thieves' Guild in Skullport

The Eye, as was originally known, was an ancient, wrinkled and paranoid beholder of Graypeaks Hive. The Eye controlled an extensive slaving operation in Skullport, rivaled only by Zstulkk Ssarmn’s outfit, and the recently resurgent Shadow thieves. It has also recently muscled in on Skullport’s smuggling operations, at the expense of its beholder rival, Misker the Pirate Tyrant. In recent the Eye had extended its control over all the beholders of Undermountain, forcing those who refused to bow to its rule to flee into the Underdark or the surface. It sole remaining rival, Misker, was forced to flee into the depths and is now in hiding in the abandoned Trobriand’s Graveyard. It's rumored that he was the second beholder to assume the name of Xanathar; his predecessor was killed by an adventures' band under orders of the Lords of Waterdeep and secretly aided by the Eye himself.

Personality
The elder orb never ventures out from its dual lairs, preferring to work exclusively through intermediaries. It is attended at all times by swarms of lurking stranglers and eyeball beholderkin. The Eye views all humanoids as slaves for the taking, but always interrogates captives to learn all that might be turned to its advantage, slaying only if it must.

Residence
The Eye primary base is in the southern half of the third level of Undermountain near Skullport in a fortified complex, but it also maintains an extensive lair in the sewers of Waterdeep, linked to its other lair by a keyed portal..