I hope to help the Shadow Priest community with progressing through the heroic modes of Mogu'shan Vaults by sharing thing I found useful during my progression. In this guide I will give tips and tricks I found useful for maximizing DPS on Elegon on 25 man heroic mode. I am not saying that everything I recommend is good or optimal and I am open to suggestions. They do, however, work and took me through heroic modes. Some tips may not work for you due to your guild using a different strategy but I will try to keep it as general as possible and mention if the tips I give are specific for a special tactic. This guide assumes that you know how the fight works.
Glyph of Mind Spike
I use this glyph for all fights where I use FDCL.
Glyph of Mind Flay
Just a generally good glyph on this fight, not like you have anything better to take.
Glyph of Inner Sanctum
You are taking a lot of damage on this boss, especially during last phase. A good glyph I think to have. You can also use Glyph of Vampiric Embrace if you feel like it. Third glyph does not matter that much.
From Darkness, Comes Light
Due to the multi-dotting on Celestial Protectors and its usefulness on Energy Charges, I recommend this talent.
Twist of Fate
There are many adds on this fight and they die quite fast. If you play well, you should have around 70% uptime on this buff.
Cascade is extremely good on Energy Charges because it will bounce on all of them if you throw it on the boss. Halo can do more damage but it is much harder to use Halo and the gain is too little for the effort.
General Tips and Tricks
I usually open like this:
You want to throw Cascade early so you will have your second one ready before the add is taken outside of the platform.Potion
Shadow Word: Pain
Shadowfiend when trinkets have procced
Keep dots on Protectors and Elegon at all times. Depending on what your raid needs, focus the appropriate target. If you want to cheese damage, focus on Elegon when he has stacks and keep dots on Protectors.
One important thing, try to not let your dots fall off when the Protectors are dragged outside the platform. You might also want to run out and Shadow Word Death them when they are under 20% for a nice Shadow Orb. The reason you want dots on Protectors before they are dragged out is to proc Twist of Fate. Make sure one of your dots is still on the Protector when it starts casting Total Annihilation, this way you maximize uptime on Twist of Fate.
Energy Charges are priority here but make sure you keep dots on Elegon. You can see his Draw Power cast and make sure to refresh any dots that are about to fall off on Elegon before adds spawn.
You have to adjust your damage on your Energy Charge according to how fast your group kills it. If the Energy Charge you are assigned to is quite easy to bring down, then maybe you should focus a bit more damage on boss or help out on another Energy Charge. The most important thing here is to throw up a Shadow Word Pain on at least one Energy Charge. The reason for this is that it will proc Twist of Fate even after the add dies. You can use Cascade every second wave. Suggestion for rotation on Energy Charge:
Throw Shadow Word Pain on another Energy Charge that you aren't Mind Spiking/assigned to if you do not have FDCL procs. Mind Spike your Energy Charge, use Mind Blast if it is ready but make sure to start casting Mind Flay at around 40% or more so you can spam Shadow Word Death on your charge to get Shadow Orb and do insane damage.
If your Cascade is ready you use it on the boss 1 GCD after Energy Charges have spawned. This way the Cascade will probably do more damage because the Energy Charges have moved a bit further from boss. So when you see Energy Charges spawn, you want to use one spell before casting Cascade.
You want to make sure you refresh your dots on Elegon before you leave the platform. You want to stand close to the middle pillar. This way you can reach all three pillars on your side and dot them. Keep dots on all three pillars, make sure to use Shadow Word Death to proc Twist of Fate on the pillar that drops below 20% first.
After pillars are down, throw Vampiric Touch and Shadow Word: Pain up on the Sparks. As soon as the platform spawns and phase 1 starts again, run in and dot up Elegon and then proceed to Mind Sear down the Sparks with the buff you get inside the platform. Use Fade so you do not have to stack up with rest of raid group (raids usually stack up so all Sparks are gathered).
You probably want to use Vampiric Embrace as soon as boss hits 20%. Your guild might assign healing cooldowns in the last phase so just tell them that you heal most with Vampiric Embrace under 20%. Other than that it is pretty straight forward single-target rotation. This is where Twist of Fate and Shadow Priests shine. Your DPS will go up by a lot.
You can use three Shadowfiends on this fight. So save your third for last phase where you Bloodlust/Heroism. Should be huge DPS boost. I am extremely horrible at thinking about how many Shadowfiends I can use in a fight and I end up using it on cooldown. Bad habit.
Best cast bar for Shadow Priest. Gnosis is the only cast bar being able to show ticks of your Mind Flay properly. There is no excuse for using any other cast bar.
Buff and debuff timer(s)
Use whatever you feel comfortable with. I personally use WeakAuras but most addons work just as well.
This is a video where you can see me using most of the tips I outlined in this guide. At the time it was a rank 1. I do plenty of mistakes because we killed this boss on like our 10th try so I did not get the chance to think about how to DPS this boss but now I have and it is written in this guide.
I hope you found the guide useful and that it will help you with your progression. If you do not agree with any of the things I mentioned, I am open for discussion. Please do leave feedback on how I can improve the guide and if you wish to see more guides like these.