The Xanathar

The Xanathar is one of the most infamous beholders of Toril and the crime lord of the Xanathar Thieves' Guild in Skullport. Most who know anything about the Xanathar at all simply know that “he” is a mysterious crime lord that has organized one of the mightiest criminal enterprises in Faerûn—other than the Zhentarim, that is.
The current Xanathar is, paranoid to the extreme, and tyrannical in nature. It clings to sanity by the barest of threads, and even its own minions fear its wrath. It craves power and flattery over all things, which puts this crime lord in a strange quandary. As with all paranoid narcissists, the Xanathar wishes to be beloved and feared by all, especially by those with power, but is so suspicious of others that it hides away from everyone out of fear that they might kill and usurp it.

History

The Eye arrived in Skullport in 1205 DR, already a slaver in search of a greater market. In time, his business and his organization grew. At one point, he re-organized his organization into a semi-autonomous model and retreated into the background, spreading rumors about his demise or retirement. Soon, most people forgot about the beholder slaver and in 1304 DR the Agents of the Eye were simply a large slaving ring in Skullport with no association with beholders.
Meanwhile, the Eye gathered information about the mysterious Xanathar Thieves' Guild, a powerful underground thieves guild, and in time discovered that they were also led by a beholder, a beholder of a different hive. Thus the Eye decided to take control, by killing and taking the position of Xanathar. The Eye discovered all of the original Xanathar's secrets and at the same time manipulated another beholder, Uthh, into wanting to kill Xanathar. Eventually, Uthh fought Xanathar in his lair; Xanathar slew Uthh but was too weak to resist the surprise attack of the Eye. The Eye killed Xanathar and took his place as the leader of the Xanathar Thieves' Guild. The Eye pretended to be his predecessor but, in order to avoid problems, said that "Xanathar" was just a title. Afterward, the Eye gathered together his agents and the Xanathar's Guild.