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Song: 戦狂乱舞 - 削除

This boss is pretty fast paced in that it requires high burst DPS in order to not get quickly overwhelmed by mechanics.

First it's best to cover the basics--head types.

There are four head types
Venomous Head (Green)
Frozen Head (Blue)
Flaming Head (Red)
Arcane Head (Purple) (Heroic addition)

Each head has a unique set of abilities that it will cast when it is in the front party and those that it will cast while in the back row. Additionally when a head is killed Megaera will grow two more of the same color heads.

All Heads - After a head on the front row has been disposed of a new set of heads will engage with Rampage for 20 seconds.

Venomous Head - While in the front party will cast Rot Armor on his current target increasing all damage taken by 10% for 45 seconds. This effect stacks.

While in the back row this head will cast Acid Rain which will put a green colored telegraph at a location. The further away you are from the telegraph the less damage you take.

Frozen Head - While in the front party this Head will cast Arctic Freeze which leaves a stacking debuff on anyone hit. This debuff freezes the target for 20 seconds if it reaches 5 stacks.

While in the back row this head will cast Torrent of Ice at a raid member leaving Icy ground in it's wake. Icy ground reduces movement speed by 5% stacking up to 20 times and deals moderate Frost Damage per second.

Flaming Head - While this head is in the front party it will cast Ignite Flesh. This is simply a stacking DoT that can become deadly if it is allowed to stack high.

While this head is in the back row it will use Cinders which is a high damage DoT that increases in potency over time. Additionally players afflicted with the DoT will leave a pool of flame every 3 seconds.

Arcane Head - This head exclusive to heroic mode will cast Diffusion while in the front party. Diffusion does moderate damage every 3 seconds. Diffusion also leaves a debuff that causes 10% of all healing received to be redirected to other raid members.

While in the back row this head will cast Nether Tear. This tear into the nether will summon 1 Nether Wyrm every 3 seconds for 6 seconds.

Nether Wyrms have two abilities, Nether Spike and Supression.
Nether Spike deals moderate Arcane damage while Supression stuns its target for 15 seconds.

Strategy:

Mechanics are punishing on this fight however, with enough burst DPS it is possible to ignore a majority of the mechanics mentioned above.

Because we know what each Head is capable we have to decide which Heads are most dangerous and which are less dangerous to let get their back row casts off.

The kill order:
Green - Blue - Purple - Green - Blue - Purple - Green
DO NOT KILL RED.

When engaging the first Green Head there will not be a Rampage so this head needs to die relatively quickly with very minimal combat CDs. I recommend Drums + PrePot + Killing spree w/trinkets.

After the first head every head will engage with Rampage. During Rampage the back row heads will not cast their abilities. This gives us 20 seconds to get the head down from full health to practically dead or else we will have to deal with a lot of potential mechanics (Especially towards the end of the fight).

This fight is all about Real-Time DPS. Each head requires at minimal 1 CD to be killed in time.

If undergeared, like myself, I recommend that you use T17 4 piece for this boss as T18 2PC is not extremely useful-- and that Adrenaline Rush by itself is already enough to kill a head during Rampage.