So wayfarer, thee have come to do Hel Ra Hard Mode?
Well sucks to be you! Pretty much one of the hardest content out there. Even now you might be CRUSHED UNDER THE WEIGHT OF A THOUSAND PAPER CUTS one the CLOUD FARTS!
Jokes aside. Here is a full strat on Hel Ra Hard Mode.
Some people might complain about that. Nonetheless it's been a year. All the high-end guilds know how to do it. No, noobs and casuals won't steal your leader spot. If they do: it's cause you suck even after one year of playing those. Grow up

So, backround, I've done Hel Ra way too much for my own good.
Usefull to know:
3 healers really help for the fight. CoP(circle of protection) at all times
Nightblades should not reaper’s mark, unless you got leet dodge skills. Veils should be dropped when adds, and also when there is a gargoyle. Call them out so that no ones drops all their veil in the same time. No veils on a add phase or gargoyle can mean a wipe.
DK should have chains and igneous shield helps for star fall
If more than 4-5 people are dead before star fall run out of the room and restart. It is a dps race and you’ll be overwhelmed. Unless you are a really experienced group and can pick it up.
Sorcerers: do whatever you want.
Tank: keep igneous somewhere in there.
To All dps: always single target boss, when adds do NOT single target, just aoe so chains can happen. Gargoyle is a priority then adds then boss.
Most important: NEVER use a synergie whatever happens. The boss will stone people occasionally and thus if you use the synergy a massive AOE happens and killes one shot everyone around you. Two options. #1: shield throw will break the stone. #2: wait that everyone is at a safe range and THEN use the synergy.
So you broke the statues, good luck. Everything does more damage and there are tons of adds.
Step 1: the group stacks on #1. Everyone should be stacked perfectly, someone off-stack and you can miss a Shield. The tank goes to #T1. The boss should be facing the group so that he shield throws the group and breaks the statue. The Raid leader should call out the shield throw so that people dodge immediately (or block) the shield throw. If someone is out of stack it will screw up the throw. He will always pause a

Step2: move to #2 and tank to #T2: rinse and repeat. Remember adds will spawn, CoP, veil and AoE adds, stack close to the boss so he is in AoE range. DK SHOULD CHAIN ADDS.Super important if not it screws the run. r important if not it screws the run. Keep an eye open for that shield throw.

Step3: move to #3 tank to T#3 and repeat.

Nota Bene: often the boss runs away, that means he is going to jump soon, stack on ONE gargoyle and the jump should break it.
Step 4: at #4 and tank T4 often there will be a gargoyle. Stack and burn. You will survive the ground pound of the gargoyle if there is CoP plus damge mitigation and good enough heals.
Step 5 and #5: stuff goes often wrong there, there are a lot of adds, gargoyle often was not killed fast enough and so on. So people should focus on keeping calm, chaining adds, go to #5 while keeping dps up.

Step 6: go to #6 and tank to T6.

After tank should bring the warrior in the middle. People should be close doing dps no one should be at 6 oclock. Far enough from tank so that if tank is stoned he can immediately break free without killing anyone: if you die cause of it: it’s your fault you where too close to the tank. When someone else is stoned call it out and people should move away. Don’t be impatient if someone is still around just say it again until that person has moved away at a safe distance.
At some point there will be a massive wave of adds: chain everything. And AOE fast. COP and mitigation. Massive heals (that’s why 3 healers). After the first mitigation is about to go out, move a bit in one direction (left or right, raid leader calls) and drop new mitigation and continue. Those stoned should break and join the group. Everyone should hold block during that phase and cast through them.
Once you have survived that wave it’s easy mode: star fall. Igneous shield of tank and Dk’s that spam it should help with the CoP+1 mitigation (veil or nova). Plus 3 heals is safe zone for surviving it. Dps should NOT be close to the boss, the least possible (Except for star fall stack) as the boss has a tendency to turn around and cleave the group. Boss also sometimes teleports randomly and does a star fall (rare bug but still happens). So if that happens: do not run to boss he’ll star fall not long after and wipe the team.
The most important is to keep proper stacking, holding block, use the synergy when no one is around and follow the procedure. Otherwise it’s a wipe. This fight is harder than the mantikora in SO so, stay frosty and enjoy