Edit:Found a video to better explain.The link its at the end of the text.Tho this guy is soloing (awesome) the boss it shows clearly what everyone should be doing.If you have a tank in the grp dont kick him.This boss its all about survival and a tank can help a lot with that by providing,shields,taunts on adds and some off-heals.If the tank has a destro staff or bow with skills,better.
First let me start by saying that I have been playing this game since release on PC and I love engine guardian helm so i always farm it.I have a lot of experience with this boss.
It baffles me ,each time I go to this boss how many ppl dont know how to kill it properly on hard mode(without using levels) and start talking about tactics that will just make it very hard for example,ignore adds and focus on boss.Adds are one of the main killers in this boss.
This is how i have been doing this boss for a long time.
First thing and most important is to stay together as a group.If you go by yourself and go away from healer you r dead.This is a healer intense fight so help your healer by staying close.
Second most important thing is adds.If you let adds accumulate its a wipe,because you have to deal with the constant damage the boos does plus adds all spread around doing damage and interrupting rez.The best thing is to wipe the adds as fast as possible then focus on boss,rinse and repeat.Use your ultimates on adds.Many dmg ults are placed on the floor and the boss is constantly moving so using it on boss most of the time its a waste of time.Tank (im a tank) should taunt adds and using LoS,try to get them together.But remember the most important thing is to kill adds fast.
Fire phase,avoid red circles as best as possible while damaging the boss.If you are melee (this boss is more easy if everyone is range,but its not a must) avoid the fire the boss do around him,it does massive damage.
Poison phase,stay close to healer while we dps the boss.The poison damage the boss does its unavoidable so heals its your only savior.
Thats basically it for this quick guide.Here hoping that it clarify many confusion about how to kill this boss on hard mode specially on PS4 NA where im playing now (my pc died
).
Remember,stay together always.Kill adds FAST.Avoid what can be avoided.And dps the boss whenever we r not killing adds.
Video link:
https://www.youtube.com/watch?v=LqlE1bFrmMI