Gjallarhorn launched in Destiny 2 with the 30th Anniversary Pack. And as if the launcher couldn’t get any stronger, Bungie also added a catalyst to it, making it even more deadly. Getting it requires a trip to the Grasp of Avarice and a few secret steps.
The Gjallarhorn catalyst is locked behind a set of secret chests in the new dungeon, which can only be opened with the Burdened by Riches buff. Three Reaver Vandal enemies will spawn in specific points in the dungeon and they’re all near a special chest.
First chest: Inside the loot cave
The first step is right at the beginning of the dungeon after clearing the first crystal and dropping further into the cave. Before jumping to the ledge with the Hive, look to the right to see a Reaver Vandal with a Scorch Cannon. Clear the Hive enemies, then damage the Reaver until it drops an Engram with the Burdened by Riches debuff.
Grab the debuff, then walk over the protruding crystal back the way you came from. The chest will be on top of a small platform in front of the crystal.
Second chest: Office, after the puzzles
The second Reaver will spawn in the office-like area after the puzzles. Hit him until you get the buff, then rush through the vent on top of the boxes. Once you’re on the other side of the tunnel, jump to the platform to your right and opposite the entrance to the boss room.
Third chest: shield area
After you’re done clearing the Fallen Shield area, you’ll find the last chest on top of a house in the middle of the last island. To find the debuff needed to open it, look for the Reaver Vandal in an area with purple covers. From the main platform, it’s located to the right of the area with the suspended turbine, and the cannon will take you straight there.
Damage him, get the buff, then launch yourself to the middle platform and head out. If you’re running Dawnblade or Thundercrash, you can make your way to the other side fairly easily. If you’re struggling, bringing a sword can help you correct your course.
What does the Gjallarhorn catalyst do?
The Gjallarhorn catalyst gives the rocket launcher an ability called “More Wolves.” This, according to the game, raises the weapon’s magazine size and “final blows with Wolfpack Rounds spawn a faster, more powerful missile at the target’s location.”
To unlock the catalyst, you need 400 kills with the weapon, so Shuro Chi can be a solid place to farm those kills. You can also take advantage of the heavy ammo regeneration buff from Starhorse’s Favor during Dares of Eternity.