Grendel of the Ashes and Frost

These will come alive at the same time near the of Chapter 10: The Black Rune. Don’t be intimidated by them since they’re quite manageable or even weak at this point of the game, especially if you kept your gears regularly upgraded. Their attacks can also hurt each other so it will be easier to lure them so their attacks hit the other. Atreus’ shock arrows can also deal significant damage especially when the two are together. Either way, this battle shouldn’t be a hard challenge. Defeat them to reveal a legendary chest. Don’t forget to pick up the loot they’ll drop. (Tartarus Rage heavy runic attack, Chaos Flame, Hardened Svartalfheim Steel x3).