The Oculus is a dungeon whose entrance is located in Borean Tundra in the World of Warcraft game. The level range for the normal dungeon is 75-80. The instance was released in the Wrath of the Lich King expansion. The dungeon contains 4 bosses. The end boss of The Oculus is Ley-Guardian Eregos.
The Oculus is one of three instances in the Nexus on Coldarra Island in Borean Tundra. It is the middle of the three, stacked one above the other. The top instance is the raid , The Eye of Eternity where you fight the corrupted blue dragon Malygos. When you get to the entrance of the Nexus, you will need to go up a slope to the dungeon, remembering, not to far otherwise you will go into the raid.
The Oculus is a multi-layered dungeon where you need to take portals between levels and to fly. You won't be able to use your favourite mount to get from level to level, you need to pick up a whistle from one of the freed captives which when you use will call a drake to fly down and pick you up. There will be three different types of drakes you can use, a Red drake will call down the tank drake, green will be the healer and the yellow of which there are three of these in the group will be of course, the dps. If you're doing the achievements, one achievement will have you have controlled each colour and another will have your group using one or two of the different types. There's not an achievement to use only one type of drake, two achievements can be done at the same time.
On entering the dungeon, you make your way through the first set of trash and then jump through the portal at the end. Drakos, a dragonkin will there waiting for you to start the fight. During the fight, the boss will create circular missiles which you need to avoid but apart from that, its all easy.
Once the boss is dead, the characters in the cages behind the boss will leave and one will be the quest hander-in if you are on the quest. There are three characters to talk to, each player in the group needs to talk to an individual. If you are after doing the achievement on the final boss, which characters you choose now allows to do the appropriate achievement at the end.
Talking to a character will give you a whistle to summon a particular dragon. Each dragon has a different expertise, the healer dragon is summonable after getting the whistle from the female Blood Elf. The red Human will give you the tank dragon and the small gnome will give you the dps. If you're after killing the boss without the tank and healer which you can do in one go, all should get the dps drake.
Before you can kill this boss, you need to destroy all 10 Centrifuge Constructs, these are giant robot like machines that are being controlled by humans and elves on various platforms one level above where you killed the previous boss. You need to blow your dragon whistle to be picked so you can fly to the next platform to kill a Centrifuge.
Only when the Centrifuges are down can you attack Varos who is on a platform on his own. Whilst flying from platform to platform, you have to be careful so that you don't pull any blue dragon and as then they will attack.
His main abilities are electricity which you need to move otherwise you'll get damage. The other ability are death rays from blue drakes which are easy to avoid but you shouldn't bother really trying to kill the blue drakes, just avoid their damage.
After killing the previous boss, summon drake and fly up to the next platform above. You'll see Urom in a shadow priest colour, approach him but he'll soon disappear leaving you with adds to kill. The first group of adds are ghostly elementals followed by ghostly creatures of Northrend then monsters of Northrend. Once all three platforms have been cleared, Urom will appear in the level in the middle. Fly to the platform but don't get too close to start the encounter.
The main thing is that he'll poison the land so the tank needs to keep him moving otherwise it might be too far to run to get out of the poison. He'll port to the centre and hang in the air and then port back and do an arcane explosion so you need to take cover when he ports to the middle. As soon as the explosion has occurred, the tank should puill him and move. Once this boss is dead, the final boss makes an appearance above so you need to
Eregos will announce his arrival after the death of Mage-Lord Urom. You need to fly the top level of the Oculus. He'll be flying around but its safe for you to land as he won't attack. You all have roles based on your dragon that you are flying. For the Eregos achievements, you need to have attempted each drake at least one, once as a healer, once as a tank and once as a dps. Another achievement is to do without a healer drake, another without dps etc. Its possible to do without healer and tank in the same attempt by all having dps. When going without dps, you need two healers to do the achievement.
Which ever spec you're doing it in, its advisable to take off all your clothes so that they don't get damaged. Health is based on the mount. Unlike other bosses, the amount of damage is static when you are on the mount, it doesn't change according to your level. You can pull the drake and then switch to ranged to kill him, that is if you have the ability.
When fighting on the mount, you can fall off and then parachute down, sometimes you can die or just fall to a platform below you. If you do fall, you'll be glad you were naked when you did it.