To fully upgrade the Axe in God of War (2018), you need Frozen Flames and a Chilling Mist of Niflheim. The maximum level of the Axe is level 6. It can be upgraded at any shop.
The axe starts out at level 1. The Frozen Flames for Upgrade Levels 2-5 are automatic drops from story bosses. They cannot be missed, just beat the story. Even if you don’t pick them up from a dead boss, they will be placed in the “Lost Items” section in the shop. So nothing is missable.
The last upgrade makes an exception and wants you to trade in the Chilling Mist of Niflheim at a shop to get the Frozen Flame material in exchange. You must have beaten the story to perform the final upgrade.
How to Get Chilling Mist of Niflheim:
Short version: from a chest in Niflheim’s central chamber that costs 5,000 Mist Echoes.
- Start by unlocking the Realm of Niflheim. For this you must find 4 Niflheim Language Ciphers in purple chests. You can find a video with the cipher locations below or refer to the text/screenshot version How to Unlock Niflheim Realm.
- Once you’re in Niflheim, talk to Sindri at his shop in the region. You can’t miss him. He gives you a favor (side quest) called “Ivaldi’s Workshop”. Complete this quest to unlock the central chamber in Niflheim.
- The Chilling Mist is inside the chest on the left side of the workshop that costs 5,000 Mist Echoes. Basically, Niflheim is a randomly generated labyrinth. You get Mist Echoes by opening treasure chests in the labyrinth. You can also sell resources you find to Sindri (the fastest way to get Mist Echoes). It’s important to note that you only keep your Echoes when you make it out alive from the Mist, meaning get back to Sindri’s shop for it to save everything properly. Once you have 5,000 Mist Echoes (takes maybe 5-10 minutes), open the chest for 5,000 to find the Chilling Mist of Niflheim inside. Below’s a screenshot of the chest in question:
- Go to any shop > Buy > Resources > Frozen Flame. This exchanges the Chilling Mist for the item you need. Now in the shop go to Upgrade > Axe (you must have beaten the story to exchange the item).
All done! After the story your Axe can be fully upgraded to maximum level (level 6). This also unlocks the trophy “Worthy”.