She was the ruler of the Night Elves for ten thousand years ago, currently she is a ruler of the Nagas. She was loved by her people, she started sinking into madness when she was corrupted by the Dark Titan Sargeras. When Malfurion Stormrage defeated her and Great Sundering sent her to the depths of the sea, she was transformed into the Empress of Nazjatar – ancestor of the serpentine Naga. It’s been said that she was the greatest mortal mage ever to live.
Some say that she is tribute to Medusa (because of her snake body and snake-like hair) and for the few features of Kali (Hindu goddess of death and destruction).
“To fully prepare for a world of perfection, all the imperfect must be swept away.”
When he was Human he was a Mage of the Kirin Tor. He was the founder of th Cult of the Damned and one of the highest agents of the Lich King. He was the reason why the plague of undeath across Lordaeron. After the plague hit he was slain by Prince Arthas. When Arthas became a Death Knight, one of his first moves was to resurrect Kel’Thuzad. As a Lich (powerful undead sorcerer) Kel’Thuzad was able to summon Archimonde the Defiler. When Arthas left from Northrend, he was left to command the Scourge of Lordaeron from Naxxramas.
Kel’Thuza wrote The Decree of the Scourge. Kel’Thuzad’s Gold Coin says “Sometimes…I wish someone would come along and just give me a big, long hug.” Also the ingame pet Lil’KT is sent to you by Kel’Thuzad and in the letter he congratulates player on joining his fanclub.