Welcome back to the Tier 14 raid guide. My name is Lore, and today I'll be showing you the 25-man normal version of the Lei Shi encounter. This is a very straightforward one-phase encounter that tends to be pretty quick to learn once you've got the basics. You'll need two tanks, and can bring anywhere from 5 to 7 healers depending on your raid team's individual strengths, although since she does have a 10-minute enrage timer and spends a large amount of the fight unattackable, the more DPS you can bring, the better.
Lei Shi herself isn't terribly complicated. She has only one attack, Spray, which she uses instead of a melee attack. She'll spam this on whoever is currently tanking, dealing a chunk of Frost damage and applying a stacking debuff to anyone standing close by. The debuff increases Frost damage taken, so you'll want tanks to be alternating whenever possible. Also, since it's an AOE, you'll want to position tanks and melee in a triangle formation, with the tanks at two of the points and the melee DPS behind her.
As she gets lower in health, she'll gain a stacking buff called Afraid that increases her casting speed. Basically this just means that as the fight goes on she'll be casting Spray faster and faster. Because of this, it's easiest to have tanks swap whenever their stacks fall off, instead of waiting for a specific number.
She also casts a couple other abilities - Hide and Get Away. Get Away is really straightforward -- she'll teleport to the center of the platform and start channeling a spell that deals shadow damage to everyone in the raid and also pushes them back. You don't want to fall off the edge of the platform, so everyone will need to run towards her while this is going on. Note that running towards her also reduces the damage you take, so even if you're not in danger of falling off the edge it's still a good idea to keep running. This continues for 30 seconds or until she loses 4% of her health.
Hide is basically just a game of hide and seek. She'll turn invisible and hide somewhere on the platform, and the only way to get her to come out of hiding is to deal AOE damage to her. There's a graphic when you hit her, which looks like a little splash of water in midair, so we deal with this ability by just having everyone run around spamming AOE's until someone spots her and calls out her location. Note that while she's in hiding, she'll be spamming Spray on random raid members, so it's important to try to stay spread out during this phase. It's also worth mentioning that there's nothing to target while this is going on, so you'll need to use non-targetted AOE's to actually hit her.
Her last ability will automatically cast every time she loses a total of 20% of her health -- so 80%, 60%, and so on. She'll put up an immunity shield on herself and summon several Animated Protectors. These guys hurt... a lot. Fortunately, you only need to kill one of them. As soon as one dies, Lei Shi will come out of her immunity bubble and the remaining Protectors will despawn. So, it's best to mark one to kill and use crowd control abilities on the rest. Instant CC's are obviously ideal, but if necessary, you can assign raiders to certain areas of the platform and have them CC whichever Protectors spawn in that area.
It's also worth having someone with an instant stun, such as a Paladin, use that immediately on the one you'll be killing. This gives the tanks a couple seconds to swap off aggro on Lei Shi if necessary, since she can still be taunted, and start building aggro on the Protector. Again, their melee swings hit extremely hard, so any non-tank that ends up with aggro will probably get 1-shot.
It should also be noted that there will actually be more Animated Protectors in the later couple of summons. Make sure you're using as much CC as possible to get them under control in a hurry. This is really the only major mechanics check in the encounter, whether or not you're able to get the Protectors under control before they can kill anyone.
Otherwise, it's pretty much just a matter of burning her down as quickly as possible. As long as you can make good use of the parts of the fight she's targettable, you should be able to get Lei Shi down in no time.