The Nexus is a dungeon in the World of Warcraft game. The level range for the normal dungeon is 68-73. The location of the entrance to The Nexus is in the Borean Tundra zone on the continent of Northrend. The instance was released in the Wrath of the Lich King expansion. The dungeon contains 6 bosses. The end boss of The Nexus is Keristrasza.
Nestled at the bottom of the Nexus temple on Coldarra Island is the location for this five man dungeon. Above that is The Oculus which is a high level dungeon (70) and above that is an one dragon boss raid (The Eye of Eternity). Getting to the wrong one could kill you, however the Eye of Eternity does need to be started, it won't start just by entering the dungeon. Whilst its possible to go round the dungeon in a anti-clockwise direction, it generally recommended and what many people in fact do is to go clockwise. The last boss, Keristrasza must be defrosted before you can fight her.
The second boss changes according to which faction you are, i.e. whether you are Horde or Alliance. The female boss of the raid, Grand Magus Telestra, an image splitting mage wears a hat during the Winterveil festival so if you're after a hat, she's the one to go for. Nearly all the female bosses wear a hat during the Winterveil festival in December.