Ruby Void

Ruby Void is a dungeon & raids achievement earned for defeating Ley-Guardian Eregos in The Oculus on Heroic difficulty without anyone in your party using a Ruby Drake.

5 Amber Drakes
This strategy requires perfect group coordination to pull off.

One person is designated to start the pull. The other four activate their temporal rifts as Eregos flies past (this will not engage him). The puller hits him twice to begin the encounter, then hits time stop and hits him one more time. At this point the other four drakes should have 8-10 charges on Eregos. Now the puller activates Temporal Rift, and the other four hit him with a single shock lance (which should hit for well over 100k due to their charges). After casting their lance, they return to rifting. At this point the puller has 10 charges (from the other drakes' lances), and casts shock lance himself, which also hits for over 100k, and gives the other four drakes 10 charges. The other four then hit him as the puller rifts. Repeat this pattern until 60%. After the arcane phase, select a new drake to be the "puller", and start over again. Eregos dies really fast on this strategy, which is the key, because you have no healing, and no tank to evade attacks.

-edit- You have to time your time-stops correctly or Eregos will summon whelps that can overwhelm the party. Also, returning to him after Astral shift and timing a time-stop is important or this will ruin coordination and he will summon whelps.

4 Amber Drakes, 1 Emerald Drake
This strategy requires perfect group coordination to pull off.

This strategy is almost identical to the 5 Amber Drake method. 3 of the Amber Drakes will activate Temporal Rift. After all 3 are up, the 4th Amber Drake designated as the 'tank' will hit Ley-Guardian Eregos twice, then time-stop, then hit him again. He will then immediately Temporal Rift. The other 4 drakes, after gaining 8-10 charges, will attack the boss, making sure the tank's Temporal Rift is up. Immediately after the charges are blown, the tank attacks the boss again and the other 3 Amber Drakes activate Temporal Rift. The Amber Drakes should be using their Time-Stops to stop the boss's Whelp Summons and Enrage. During this time, the Emerald Drake will keep a 3 stack on the boss, a 25%- damage debuff on the boss, and a heal on whoever needs it, mainly the tank. It is strongly recommended that the Emerald Drake prioritizes his own health before others as his death early in the encounter almost ensures a wipe. At 60%, the boss will go immune and summon orbs. During this time, all the drakes need to fly away from the orbs. Also, any Amber Drake that used Time-Stop should blow their 5 charges on any whelps that have been summoned to kill them quickly before the boss re-enters the fight. By this time, if the whelps haven't died, the Emerald Drake is going to have to stop healing and start applying 3 stacks to the whelps as he will pull threat and not be able to heal or debuff the boss since both make the Emerald Drake lose its own health. During the 2nd cycle, the Amber Drake with the most health should be the new 'tank'. The cycle repeats until the boss goes to 20%, at which point he will phase out once again and everyone has to fly away from the orbs, killing any whelps they can. At the last 20%, it is STRONGLY recommended that the Amber Drakes keep the boss in a constant Time-Stop as he is weak enough to die by the end of it. Note that diminishing returns apply so only so many can be applied, depending if you've already Time-Stopped recently. Make sure coordination is strong and Time-Stops aren't used at the same time. This is a tough strategy but easier than the 5 Amber Drake strategy.