What the achievement asks
Defeat Vol'zith the Whisperer in Shrine of the Storm on Heroic difficulty or higher. Ten points, both factions.
The shrine is the tidesage seat of power in Stormsong Valley, and the dungeon follows the corruption that drove Lord Stormsong mad.
The four encounters
| Order | Encounter |
|---|---|
| 1 | Aqu'sirr |
| 2 | Tidesage Council: Brother Ironhull and Galecaller Faye |
| 3 | Lord Stormsong |
| 4 | Vol'zith the Whisperer |
The raid Crucible of Storms sits directly beneath this shrine, and it is only two bosses long. If you are working through Battle for Azeroth for the meta, the two are worth doing on the same trip out here.
Heroic or higher, but on one character
Blizzard's wording is "on Heroic difficulty or higher", so a Mythic or Mythic Plus run earns it just as well. There is no need to queue for Heroic specifically.
The eight Heroic dungeon achievements are not account-wide. Four on your main and four on an alt leaves you with nothing. They all have to be earned by the same character.
Once one character holds all eight, the Battle for Azeroth Dungeon Hero achievement they feed into is account-wide, so the grind only has to happen once.