Can I Get A Helya

This Achievment is not included in the 43 appearance sets listed and is the reward for completing the Trial of Valor: The Lost Army

I was trying to collect this appearance for the achievement, so I did like people said here, I started on normal. As a fury warrior, the only way to keep both bosses appart in the first fight is to wait for one to stop moving and cast, Heroic leap away so the other one follow and lose the buff. You can kill, and quickly charge the second one (the one that was casting) to bring him appart and finish the fight.
I took the quest, finished the raid and got fragments.
Then I tried it in Heroic. It was the same thing, as easy as normal.
But when I killed Helya, I got [item=143518] the ensemble in Heroic. It then gives you the achievement.

Conclusion: If you are only trying to get a set for the achievement, regardless the difficulty/color/appearance of it, do the raid in heroic (take the quest too). You have chances to get the ensemble the first run if you're lucky, and if not, you get more fragments in heroic than normal mode.

Easy Solo for Level 120 Battle for Azeroth or Level 60 Shadowlands and Beyond...

1. Choose your Difficulty. Normal, Heroic, whatever you are capable of.

2. Defeat the first two by keeping them separated by like 35 yards, obviously pet class makes this so much easier.

3. Defeat Odyn.

4. Accept his Quest and go into Helya's domain.

5. Defeat Guarm, loot the Valarjar Soul Fragments.

6. Defeat Helya, loot the Valarjar Soul Fragments.

7. Rinse & repeat Weekly upon raid reset, until you have all One Thousand Valarjar Soul Fragments.

8. Turn in to Odyn and Receive your Just Reward.

9. ?

10. Profit. Achievement Completed.