Forgive me, but I just copied my response in another thread.
I did this as BM at about 618ish, I think. I attempted this over multiple days with different builds and finally got this done.
I imagine there are lots of ways to approach this. This is what worked for me.
Pet Taunt Off
You are mostly face tanking this and sometimes Brann
I only MD to Brann
I hit the boss several times before I let my pet go in and my pet only died once in the fight.
I took my Delve build and then got rid of things I didn’t need and tried to buff my pet as best as I could.
I used a new UI set up for my bars with only the things I needed for the fight. And I moved my spells around to help me remember that I was changing my rotation.
I adjusted my gear to give me increased speed - I find my reaction time is a bit slower now and I kept barely getting clipped by things.
I had Hearty Food and Flasks and the typical. I also healed a soldier in the Hallowfall infirmary which gives a 2 hour buff that heals a small amount every 5 or 10 seconds. Lasts through death.
Used Brann as heals and Amorphous Relic and Porcelain Arrow
This is not a DPS race. It is a long haul mechanics fight.
I saved BW, DB and most KC for the eggs. I was mostly just trying to maintain frenzy stacks with an occasional CS or KC on Zek
Keep him in the center of the room and you are less likely to have the egg spawn in a corner.
You need to stay close enough to get out of fear but not so far you can’t avoid the cone (speed helps)
Only Disengage for Spittle, if Brann doesn’t get it. This was SO HARD, because I use disengage all the time.
And Disengage TOWARDS OR THROUGH the boss. I tend to move away and would then get caught in the cone. This was very hard to train myself to do.
There is a rhythm to the fight of constantly moving out and then back in.
Macro to target boss and cast interrupt and then back to last target. Seemed the heal would often happen when dpsing the egg. This interrupts and gets you back on the egg.
Blew all cooldowns on egg and once it did spawn but Intimidate DOES interrupt and gave me a chance to finish it off.
If you stay close to him and keep him near the middle, Brann’s pots are more likely to be near you and not on the other side of the room.
When Zek melees you, there will be 3 hits and likely kill you, especially if he crits. This is when you run over the healing pots. If you are staggering a few seconds between each one, the initial heal and heal over time will get you through it as you run away.
***This was THE BEST ADVICE ANYONE GAVE ME AND WAS A GAME CHANGER
I also had my own healing pots and the Cave Dweller ones as well.
Phase 1 is awful and nearly all my attempts were getting through this. Once I got to Phase 2, it was less than 20 attempts to finish it.
Phase 2, you need to avoid standing between the portals because the spell damage travels through them
Top down camera to avoid the spikes.
The 4 Orbs are cast from his Front, Back and 2 Sides, so look at how he is facing.
I never watched his health during the fight until I realized he was nearly dead and nearly scuffed it.
My fight was nearly 10 minutes long because I was extra careful to have enough dps for the egg and was likely overly cautious.
It took me just over 300 attempts and I don’t care who knows that. I’ll bet half of them were a fail in the first minute because I was always too far away or getting clipped.
I made a ton of mistakes and needed to change a lot of muscle memory. I kept tweaking my rotation and approach. I also panic easily and tend to get focused on the next thing coming and bork what I am doing.
Once I recognized the rhythm of the fight and how to use the healing pots effectively, things changed.
This fight is brutal. However, if I can squeak my way through then any of you can as well.
I hope some of this helps
Good Luck to everyone still working on this