In order to get the coveted Year 3 Gjallarhorn launcher, you have to first collect seven Iron Medallions, metal plates shaped into a wolf's head, and bring them back to the Iron Temple. Here's where to find the Iron Medallions.
First, check out How to Get the Year 3 Gjallarhorn Exotic Weapon and follow the instructions until Tyra Karn tasks you with finding the seven Iron Medallions. Then start up a Patrol in The Plaguelands to begin your hunt. Each Iron Medallion lies in a single location, with only one per location. It won't ping during navigation mode, and a symbol will only show up on your HUD as a pyramid-shaped icon if you're close to one. Also please note that the Iron Medallions will not appear until you start the Beauty of Destruction quest. Here's their individual locations:
For more tips and hints for Destiny: Rise of Iron, visit our Destiny: Rise of Iron Guide Hub.
Felwinter Peak – From where you first spawn, head up the stairs to the left that lead to Lord Saladin, but stop about halfway up and look at the rock formation to the left. The snow-covered outcroppings are big enough to jump onto. Climb upwards until you get to a wolf statue, then jump to the right to find the Iron Medallion on top of the small peak.
Lords' Watch – From where you first spawn on Patrol, go to the right until you see a small shack. The Iron Medallion is on a shelf next to the entrance to the shack.
Giant's Husk – To the right of the entrance to the oil tanker is a snow-covered platform high above the ground with storage containers and a crane on top of it. Go towards the crane and search between the storage containers there. The Iron Medallion is in an alcove formed from several red containers just past the crane.
Archon's Keep – From the entrance to the structure that leads to Archon's Forge, look to the right towards an overhanging wire and a pile of junk. The Iron Medallion is in that pile of junk, though it probably won't register on your screen like the other Iron Medallions, ostensibly because it's buried. Use the pyramid icon on your HUD to guide you to its location.
Site 6 – Enter Site 6 from the vents as you would during the last main mission in the Rise of Iron main questline. Head to the big, open part of the first room and dispatch the enemies you find there. You'll find the Iron Medallion in the corner to the left of the Splicer Gate.
Forgotten Pass – On the side of the bridge furthest from Archon's Keep, you'll find an Iron Medallion on the ground in the middle of the road.
Bunker Triglav – At Bunker Triglav, you'll see a battle going on between the Fallen and Hive. Enter the large building on the Fallen Splicers' side of the battlefield and go in the first room on the left. Go through that room to the next one and look at the floor by the door, where you'll find an Iron Medallion.