It seems like a really hard fight at first, once you've run through this fight a couple of times however it should be rather easy to complete.
Unbalancing Strike: Inflicts 350% weapon damage, also unbalances target reducing defense by 100 for 6 seconds.
Uppercut: Small knockback attack
Arcane Burst: Extremely high damage AoE spell activated when in melee range
Shadow Bolt: Deals 2200-2800 damage
Blizzard: Deals AoE 900-1650 damage
Scarabs: Has the ability to turn nearby scarabs into 3000 damage fire bombs
The key to this fight is positioning, the emperors must be more then 60 or so yards apart otherwise they heal eachother. Everyone 35-45 seconds the emperors will teleport switching places with eachother, they are rooted for a few seconds each time they switch.
The emperors share the same HP and thus if one dies both die. Also when the emperors switch use aspect of the pack to speed up your DPS groups to get to the correct emperor.
The initial pull can be a killer, the right side is the melee emperor and thus just pull him like any melee mob. The left side has to be at range, keep him there until the emperors teleport.
When the Emperors switch places the MT who gets Vek'lor needs to run out of range extremely fast lest he be killed by the arcane burst. Never attempt to DPS Vek'lor just focus on Vek'nilash instead.
Vek'nilash can slaughter even the best tanks with a couple unbalancing strikes, keep the healers perfect on him otherwise your tank might die. One you get the hang/timing of the teleports this is a rather trivial fight.
Also make sure your healers/casters avoid Vek'lors nasty blizzard spell and keep your casters ready to take down the bugs that come.