Updated Wed, Nov 19, 2008 by Messiah
The second instance that you are will likely visit in the Wrath of the Lich King expansion is the Nexus, located in the Coldarra area of the Borean Tundra zone. The instance is the lowest level instance located at that hub and is meant for players level 71-73.
The instance location is not the easiest to find, and really depends on you following quests in the zone and their progression to find your way there. As you make your way east and north out of the Alliance Town you turn north to find Amber Ledge. Once there you can fly across to Coldara and a small quest hub. The second round of quests located there direct you into the Nexus to explore.
The meeting stone and instance portal are just north of the quest hub area and into the mountain. The whole area is a carved crystal-like cave structure. Everything is carved and glimmering, giving it a palace like feel rather than feeling like you are in a save.
Once inside you are greeted by a foyer and several corridors. In the foyer lies the frozen dragon, Keristrasza, who can only be freed by defeating the other 3 bosses in the instance. Each of those bosses is found down a wing of the instance, and there is no set order in which you must complete them, making the instance very free flowing. The three preliminary bosses are all very different from each other, there is the energy wraith Anomalus, the earth elemental Ormorok, and the Elf Grand Magus Telestra. Once they have been defeated you can return to the entrance and release Keristrasza and attempt to defeat her.
Anomalus is an energy based boss that is found by venturing out among several floating platforms connected by walkways. In this area there are several energy rifts that you need to destroy or they continually summon in additional MOBs. These help prepare you for the boss fight, by learning what needs to be done with them. The area, while nice scenically, is a little bit of a pain to move around in as the connecting pathways between the platforms are not really visible while on a platform unless you change the camera angle to look down from above. Several times players got stuck not knowing how to continue on or go back.
Once you make your way through the area you find an energy wraith based boss on the last platform name, Anomalus. The biggest issue while fighting Anomalus is that he becomes immune to damage every 25% health that he loses and opens a rift. You must destroy the rifts before they summons to many adds, and then continue to fight Anomalus. This repeats 3 times before you can finish him off and win the fight.
The next boss that is found located through a crystal forest area. The area has several tree-like elementals and tons of annoying plant creatures. The plants can be defeated, but just ball up into seed form, to be released shortly later to harass you on your way out of the area.
The boss is an earth elemental type boss called Ormorok the Tree-Shaper. He is a huge colossus that can hit fairly hard, dealing roughly 2000 damage to a tank per hit. Throughout the fight he casts a crystal spike attack, that grows spikes out of the floor around him. In this phase you must quickly avoid them, or you will get thrown into the air and take damage from them and the fall. It is not that hard to sidestep them though, just be ready for it. Lastly, once you have him down to 25% health he will enrage, causing more damage per hit. Overall he is not a very difficult fight, as all you need to do is move slightly during each round of spikes.
The last of the preliminary bosses that you fight is found in a crystal library (or study) area and named Grand Magus Telestra. This is probably the most interesting fight in the instance as she has three very different phases. In her first phase you must attempt to tank her while she throws people around the room and up in the air, so it has a very similar to the Kael'thas fight in Magisters Terrace. While doing this she will be casting fireballs and blastwaves, both of which can hit pretty hard (up to 1500 damage).
Once she reaches 50% health, she disappears and 3 clones appear. Each clone has a different spell school, and can be CC'ed. The arcane version uses arcane explosion and polymorph, the frost one castes ice bolts and blizzard, lastly the fire one spams scorch. Kill all three as fast as you can. If you have CC leave the frost to last and control it and it seems to do the most damage, if not kill it first so you take the least damage.
Once the clones are dead, Telestra will reappear. You continue the fight as previously down to about 20% health at which point she does a huge damage AOE fire attack to everyone within casting range. It is best to time this to have cloth and leather wearers clear out of the range before dropping her to 20%. Once down below that, just continue to burn her down.
Now that all three bosses are dead you can return to the front foyer and activate the orbs around the frozen dragon and free Keristasza. She has two special abilities in the battle. The first is a tail attack that hits anyone in her rear arc for a lot of damage and sends them flying. It sends them far enough that they may be out of healing range, so it is best to fight her from the sides. Besides her tail she has a stacking debuff that has a chill effect. Basically if you stand in one place it stacks causing damage, and slowing your movement, attack speed and casting speed. When you move it is removed, so the whole fight everyone needs to keep moving. The best thing for players to do is to stop then attack, cast or heal, then move a few steps. Continue this for the whole fight and you should be good.
The fight is a little anti-climactic after the Grand Magus Telestra, but the chill mechanic is a very interesting one, and one that I hope we see in other fights as well.
Overall the instance is pretty quick taking an average group about an hour. While meant for level 71-73 players, it should not be an issue to anyone coming in to the expansion to complete right away if they have done any raiding in the Burning Crusade. It is easily tanked at 70 with just Karazhan, Zul'Aman and Badge gear and at that level tanks can pull and survive whole rooms at one time and make it through the instance with no incident.
The instance is very well paced, which is exactly what Blizzard stated they were going to try to improve on in WotLK. Each of the three areas had a very different look and feel, and you could move between them quickly and easily. The crystal forest especially is a cool area, both visually stunning and has a few cool effects.