A bit about the fight. The percentages won't be exactly right because this was from observations I had made. The Emperor summons his adds 3 times during the fight. At 100%, 70ish%, and 50-40%. The Emperor will ONLY cast spells that hurt a lot! So you need to constantly watch out for him even while killing his adds. Many people get to the 50% mark and then somehow get one shotted. That is his Force Blast ability. Right after he spawns his 3rd set of clones he will start almost chain casting this ability. If one of these hits you it will most likely result in a frustrating death. This fight is incredibly hard but by no means impossible. It can still be done in legitimate ways without relying on bugs and cowardly tactics!
A Very Detailed Emperor Strategy for Jedi Guardian Defense Specced
First Set of Adds:
The fight is doable even for a T7 with level 14 gear and a bit of luck. T7 has an ability called EMP Blast or something similar which wipes out all of the Emperor's clones in one hit. Activate it for T7 to use. I suggest when first starting the fight to have T7 take the hate and use his EMP blast to get rid of his first set of clones. Before he dies make sure to use Saber Ward and Call of the Force. You should be nearly at full health with the CotF HoT on you. Once you kill his first set of adds it is just a matter of interupting his abilities which you have many means to do so. For this fight you have to utilize a lot of moves. Use any means necessary to interupt his casts. Force Push, Force Stasis, Kick, Hilt Strike, Force Leap, and if your all out of options hide behind a pillar.
Second Set of Adds:
At 70ish% health he will summon his second set of adds. If you are lucky T7 might still be alive to drop his EMP bomb. If not, use Awe once all the adds have come into range. Don't worry about interupting the adds abilities, just worry about killing them. They usually die with one hit by a special ability. So during the duration of the stun try to kill as many as possible. If adds are still up after the duration of Awe use Force Push or Force Stasis to distract the real Emperor. If you end up getting around 60% health or below this is the time to use some CDs. Saber Ward should be up again if you used Call of the Force before your companion died. Once the adds are down you can either fight it out with the Emperor or stall for time to wait for Awe to come back up by LoSing the Emperor and interupting him.
The Last Set of Adds:
This is the most difficult and pivotal part of the fight. As soon as he spawns his 3rd set of adds he will start casting Force Blast. If not interupted this move WILL KILL YOU. If Awe is back up don't hesitate to use. Use Warding Call, Enure, Medpacs, ANYTHING to help. Kill as many adds as possible but make sure to keep an eye on the Emperor! You have to interupt Force Blast. If you are able to kill the adds you have the fight. The Emperor will ONLY cast Force Blast and luckily it has a very long cast time.
If you have any questions feel free to reply and GL with the Emperor.