Ready for Raiding II

This achievement requires Strike at the Heart or Strike at the Heart, which is the final stage of druids / warden's daily questline.
You have to complete Calling the Ancients to unlock it.

※ If you failed, just wait a few minutes for respawn.

◆ [npc=53759]：

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• [spell=99992] - Run away while he casting. You will be rooted if you hit by the web
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• [spell=99991] - Spawn few spiders after few seconds, cannot avoid. Just aoe them down.
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◆ [npc=53771]：

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• [spell=99998] - Run away from the boss.
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• [spell=100154] - Interrupt or just run away asap. The active radius is quite huge.
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◆ [npc=53864]：

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• [spell=98035] -Put a fire pool looks like Magmaw's [spell=78006] under your foot and will burst after few seconds.- Run away asap.
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• [spell=100264] - A fire breath works like Mimiron's [spell=66490].Tthere will be a red mark on the ground [spell=100267] that shows where the breath begin.
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◆ [npc=53834]：The hardest one to get credit.

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• [spell=100237] spawn a fire pursue you on the ground. You will get debuff [spell=100222] if the fire reach you, and the achievement failed.
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◆ [npc=53055]：

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• [spell=99101] - Throw a javelin to a target. Few seconds later lots of lava balls erupted from the javelin's placement and you can see their shadows on the ground. Just run away form there.
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• [spell=98315] - It works like Zanzil's [spell=96914]. Notice that he will cast it continuously about 5 times, start moving while he is facing you!
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If you are going for the achievement only, do this: Go through the daily quests one day to get to the final quest which is Strike at the Heart but do not turn it in. Getting through the preliminary quests is time consuming and you only have to do it once. At the time of this post you do have to be on the quest and activate the tree to engage any of the bosses. The bosses change every day. So after getting to Strike at the heart do not turn it in. Come back every day and a different boss will be up for you to kill and you just simply activate Witherbranch (the big tree) without going through the long quest line.

Evidently, being ready for raiding in this tier means standing 100 yards away and being in the group while contributing nothing and still getting credit for the kills.

Sounds about right.