What is Zin-Azshari in World of Warcraft

Zin-Azshari ("The Glory of Azshara" in Darnassian) was the lavish capital city of the night elves 10,000 years ago, built on the banks of the Well of Eternity. The previous name of the city is unknown, but, after her ascension to the throne, it was renamed after their beloved Queen Azshara.[1] Within its highest spires, the Highborne set themselves to plumbing the mysteries of the Well. When they ultimately contacted Sargeras, Zin-Azshari became the beachhead through which the Burning Legion poured. Most of the city was left to ruin almost immediately, as the first targets of the Burning Crusade were the non-Highborne inhabitants.[2]
When the Well of Eternity exploded, most of the city slid deep into the newly-formed Great Sea as the Maelstrom began its creation."[3]
From WorldofWarcraft.com's Story section:Somehow, against all odds, Queen Azshara and her Highborne elite managed to survive the ordeal. Tortured and twisted by the powers they had released, Azshara and her followers were dragged down beneath the raging sea by the Well's implosion. Cursed - transformed - they took on new shapes and became the hateful serpentine naga. Azshara herself expanded with hate and rage, becoming a massive monstrosity, reflecting the wickedness and malice that had always hidden within her core.

It seems that the transformation experienced by Azshara and the Highborne was caused by the Old Gods. As her world crumbled around her, the Old Gods told her they could help. Azshara agreed and was transformed. The dark beings then said that when the time comes, she will serve them well.[3]
Thus, Nazjatar and the naga were born.