Emerald Void

This achievement and the Ruby Void (No Ruby Drake) achievement can be gained very easily together in one run by using nothing but Amber Drakes (Yellow).

My group of guildies and I did this just yesterday with a small amount of practice and good communication over ventrilo.

Once you're ready to engage Ley-Guardian Eregos, make sure everyone has the Amber (Yellow) Drake. If you have a priest, paladin or druid in group get these players to buff every other players drake while they're sitting on them, then buff their own after they call it and targeting it before your character jumps onto its back. Once everyone is ready you will stay in a group and be ready to kite anti-clockwise (preferably because the boss is already patting this way).

Here is the tricky part. Every Player must know the mechanics of the Amber drake.
They have:

Button 1: Shock Lance (60 yds) - Instant - Deals 4822 to 5602 Arcane damage and detonates all Shock Charges on an enemy dragon. Damage is increased by 6525 for each detonated.

Button 2: Stop Time - Instant - 1 min cooldown - Halts the passage of time, freezing all enemy dragons in place for 10 sec. This attack applies 5 Shock Charges to each affected target.

Button 3: Temporal Rift (60 yds) - Channeled - Channels a temporal rift on an enemy dragon for 10 sec. While trapped in the rift, all damage done to the target is increased by 100%. In addition, for every 15,000 damage done to a target affected by Temporal Rift, 1 Shock Charge is generated.

Once you engage the boss, four of your players will be spamming Shock Lance hitting the boss with normal attacks while your fifth player will use Temporal Rift as soon as the fight starts. Once this player channeling has reached 10 stacks on Ley-Guardian Eregos he will need to call out for everyone to channel. Whilst every player is channeling, your fifth player uses his 10 stacks and nukes the boss for huge damage, in turn stacking every other players channel and allowing them to use an instant nuke also.

How this works is, Temporal Rift stacks from damage other players do. If you have 10 stacks you can use these 10 to stack other players Temporal Rifts by waiting until they have their Rift on the boss then letting fly with your attack, stacking their Rift. With practice you could even seesaw these attacks off each other and only ever need to use Shock Lance at the start, however it is difficult due to lag and player reaction time.

From here you repeat this process where the same person channels while the other four continue to stack his attack with your primary attack.

During this time the players who are not on Temporal Rift full time will be using Stop Time in a rotation.

Player 1: Stop Time a few seconds after engaging combat
Player 2: Stop Time a second after Player 1's Time stop ends.
Player 3: Stop Time a second after Player 2's Time stop ends.
Player 4: Save Stop Time due to diminishing returns on the boss.
Player 5: Save Stop Time due to being on full time Temporal Rift.

These Stop Times are vital due to player 5 essentially "tanking" the boss. Time stop will reduce incoming damage by a huge amount and allow you to nuke without any worries. If this is all executed correctly the boss will fall into the void (Immune + Transparent) and spawn sparks without any whelps spawning at all.

Kite away in an anti-clockwise rotation around the edge of the sky box away from the sparks and once the boss comes out of the phase go back to engage him (only go back if there are no whelps. If you have whelps spawn, let him come to you as he flies faster than whelps).

At this point Player 4 should Time stop once everyone is within firing distance and repeat what you did at the start of the fight, rotating channels. It is advised to have a different player on full time channel as it could help keep your original "tank" alive by pulling aggro, and also free him up to use his Stop Time. By this time players 1, 2 and 3 should be close to having another Stop Time also. Remember to use three Stop Times in sequence and do not waste them!

Once you've used all your Stop Times, the player with aggro should be flying anti-clockwise around the room kiting the boss trying to avoid any excess damage while your other four players attack him with their Shock Lance. This should be all that needs to be done to finish off the boss. With a little practice and a lot of good communication it is a very easy fight for two achievements in one.

Good luck to everyone trying and I hope this has helped.
Remember not to release if you die, we pulled this off after one of our players fell and he still got the achievement.

This achievement (and Ruby Void in conjunction) can be pulled off semi-reliably by using 5 Bronze drakes.

The basic idea is to do enough DPS to make Eregos phase shift without doing much damage to your drakes and without any whelp spawns. The rundown is something like this:

1. 
   
2. A "starter" drake uses Time Stop, which grants 5 Shock Charges, then uses the channeled spell (Temporal Rift).
3. 
   
4. While the first drake is channeling, the other 4 drakes are spamming Shock Lance to build up Shock Charges for the first drake.
5. 
   
6. As soon as the first drake reaches 10 Shock Charges, the other 4 immediately begin to channel.
7. 
   
8. When the other 4 are all channeling, the first drake uses his Shock Lance. The damage done by the Shock Lance (about~140k) causes the other 4 drakes to instantly build up 8-10 Shock Charges.
9. 
   
10. The other 4 drakes use Shock Lance again, all hitting Eregos for ~140k x 4.
11. 
    
12. The process starts over - one drake uses Time Stop and begins channeling to build up Charges, the other 4 drakes spam Shock Lance until the "starter" drake has 10.
13. 
    
14. Skip to step #3.
15. 
    

You can use Time Stop three times during each phase - after the third stun Eregos becomes immune. After the third Time Stop has gone off, Eregos should be shifting phase soon after and everyone should scatter to avoid the arcane/lightning/whatever balls. Additionally when Eregos shifts back into his attacking phase, the Time Stops from the first two drakes will not have come back up. This means you'll need a rotation on which drake acts as the "starter" drake. You'll need to coordinate your rotations before engaging to successfully pull off a kill.

Keep in mind that even when well executed, there's still some luck involved with this strat; it's possible for Eregos to summon whelps when he's active after the 2nd/3rd Time Stops. It takes some learning to get it down in general (even knowing this strat ahead of time my group took several tries to pull it off). It's not bad once you get it figured out though, definitely easier than other achievements.

Hope this helps, and GL.

Our group devised our own strategy from scratch (though I have seen similar ones on this thread. This is a copy and paste from what I wrote on Ruby Void). I'll have to disagree with both the above commenters and say that using stun 6-8 seconds into the fight almost guarantees that you get no whelps. DPS will be fine without using stun for the charges. For us stun is a way of preventing him from spawning adds, not giving us charges. If the stun rotation is executed perfectly this way you won't see whelps at all.

Basic info:

Temporal Rift does NOT stack. The bonus will always be 100%. (To clarify you can have more than one Temporal Rift up, but the bonus damage does NOT stack.)
The Time Stop does indeed have a DR.
You can stun him for about ~16 seconds per phase.

Strategy:

The basic strategy is to play static charge ping pong with this guy. Have one designated amber drake to pull with a Temporal Rift. The other four drakes will spam shock lance until the first drake has 10 static charges. Then the four drakes using shock lance put up their temporal rift, once all four are up the first drake with the 10 charges detonates his charges using shock lance. If executed properly this gives every drake with temporal rift on the boss an automatic 10 charges. The first drake will put up rift immediately after shock lancing. Then the other four drakes shock lance. As you may have guessed the first drake will have an automatic 10 charges. So you just keep doing that rotation and you will do insane DPS. He should go down to 60% (when ethereal phase starts) if executed properly within ~15-20 seconds.

The stun factor. If your group is competent then you can afford to use the first stun after the four drakes detonate their shock charges. Let me say that whelps spawned based on time as far as we have found. Stunning around 5-8 seconds into the fight is ideal. You want three of your four drakes to get the stun rotation from 100%-60%. Have a defined order and if it helps have someone calling out when to do it. As mentioned 5-8 seconds into the fight for the first one then just use them as he comes out of stun.

Coming out of phase 2 (when he is at 60%) you will want your main rifter (the drake who opened with a rift at the pull) to time-stop off the bat and use rift. He will get 5 charges from the time-stop and it shouldn't take as long to get the other five. The other person who hadn't used stun at this point should use his/her's after, then the first stunner's stun should be off cool-down for the third. If you have problem with whelps coming out at the end of this phase I would suggest switching it up and having the main rifter using hit stun AFTER he detonates his first 10 charges.

After ethereal phase just keep the rotation up as you would normally. Never try to just burn him with shock lance if you have adds sub 20%. Stay calm and keep the rotation up and he will die fast.

This strategy is easy, though it seems like some people need time getting used to how it works. Basically after you get one person their 10 charges all you are doing is using Temporal Rift, and one shock lance, and repeating that.

Note: When you use temporal rift and someone detonates their 10 charges you get 10 charges yourself. Stop your temporal rift as soon as you get 10 charges. NEVER EVER let the temporal rift channel to full when you have 10 charges already. Its a lot of wasted DPS. You have to break channel and be ready for shock lance once the temporal rift(s) are up.

For the person doing the main rift, it is suggested you call stuff out. Once you have your 10 charges, call for people to use temporal rift. Once you see four up you use your shock lance and IMMEDIATELY put up your rift and call out for them to use shock lance and repeat that until he goes to etheral. Have someone other than the main rifter doing stun call outs (after the pull count to 7 or 8 and tell the first person in the stun rotation to stun, then once stun is up tell the next person etc. Straightforward.)

Another tip is to have your main rifter (first person to use temporal rift) to stand apart from the group so you can the other members can shock lance the second they see the animation. Reduced our time on p1/p2 by a few seconds.