Varo'then

Varo'then was the leader of Queen Azshara's personal guard during the War of the Ancients.

War of the Ancients
Varo'then was the leader of Queen Azshara's personal guard and bore a distinctive scar. While hardly at the level of a Highborne sorcerer, he had his skills with the arts. After the "death" of Xavius, Varo'then became the right hand of the queen. Outwardly, Varo'then was immune to Azshara's charms, but in fact he was madly in love with her. Unlike Xavius, Varo'then dealt with his obsession by serving the queen's every whim. Mannoroth found Varo'then annoying, but very efficient, meaning that the captain was the best-liked of the Highborne serving the Burning Legion. Varo'then and Illidan were sent to retrieve the Demon Soul from Deathwing. He succeeded and gave the Demon Soul to the pit lord Mannoroth (Varo'then nursed a vendetta against Malfurion for the remainder of the War of the Ancients). At the final battle overhead the Well of Eternity, Varo'then led the Highborne still loyal to the queen on the backs of large, mysterious, flying bat-like creatures. There, he was slain after admitting to Malfurion that he lived only to serve Azshara and gain power to lead her forces, even to destroy Kalimdor. As his confession had rejected Kalimdor, Kalimdor then rejected him.

World of Warcraft
In the Azshara zone on the eastern side of Kalimdor, there was a small area called Shadowsong Shrine. There were ghost mobs in this area with Varo'then's Ghost among them.

Cataclysm
Varo'then appears with Mannoroth as a boss encounter via the Caverns of Time in the Well of Eternity dungeon in patch 4.3.0. After he was killed, his sword was then used by adventurers from the future to defeat Mannoroth.

Varo'then's Ghost has moved from Shadowsong Shrine to Lake Mennar.

War of the Ancients

 * "The Light of Lights will reward me greatly for this!"
 * "Mannoroth fell afoul of you!, Archimonde fell afoul of you! Such an insipid creature and you outwitted them both! Lord Sargeras's grand commanders! Ha! I'll not only again be her favored for this, but his as well! Me! Lord Varo'then!"

Trivia

 * Varo'then's sword looks like the sword from what Taylor used at the battle at Serpent's Heart.
 * Mark of Varo'then is a drop from Kur'talos Ravencrest.