God of War - The Black Rune, Tyr's Vault Water Puzzle solution, Grendels boss fight

The Black Rune, Tyr's Vault Water Puzzle solution and the Grendels boss fight come towards the end of God of War PS4's main story.

Here on this page, we'll take you through everything you need to know about this section of your quest, including how to solve any puzzles, take down any bosses and find any useful loot along the way. For guides to specific collectibles we also have pages on Valkyrie locations and how to open Hidden Chambers, Lost and Found locations and Faces of Magic locations, too.

This page follows on from God of War - he Black Rune, Tyr's Vault Water Puzzle solution, Grendels boss fight, and is the sole page on the mission.

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Otherwise, you can always cycle back to our main God of War walkthrough and guide hub, too.

The Black Rune and Tyr's Vault puzzle solutions

Having thankfully cured Atreus of his ailment - and also finally revealed the truth to him about your (and his) status as a God - it's time to get back to your quest to Jotunheim once more.

Return to Tyr's Bridge, and the once-locked room on it that serves as the entrance to Tyr's Vault, so you can try to find that Black Rune you need to continue your quest.

First up, use the rather simple sand bowl here, which literally just requires you to command Atreus to write the word on the wall in front of him into the sand.

You'll soon descend into the vault, where Atreus will spot the rune you're after, but it's soon wrapped up in three protective rings, forming a huge hovering orb in the middle of the room.

Your task then is to open those three protective rings - and that's done by solving puzzles in the three chambers that branch off from this central one.

Deactivate the Vault's Defences

First, go to the door to the East that's now open, into another chamber. You'll see a wind trap there - you need to take the green wind from the spinning ring itself that's in the central room, and put it in this trap.

This will cause wheel to pop up and replace the wind trap. Spin it, and you'll open up two corridors from this first chamber: one to a Coffin chest, and one to the next side chamber that you need to reach to lower those defences. Both of the corridors are booby trapped.

The path to to the coffin is to the North-East, and is easier to get through. Throw your axe at the little disc targets on either side of the big spinning blade disc, and do the same again for the one behind it, and you can get down the end of the corridor to the Coffin.

To the North-West is the path to the next chamber, and it's a bit tougher. The first you thing to do is time a sprint through the first two blades just after they separate.

Then, you have to hit a glowing cog on one of the next two blades that are spinning together,and it'll freeze it in place whilst the other blade continues to rotate around. When the two line up, recall your axe to unfreeze it, and you'll have created space to run by.

In this second side-chamber you'll trigger a cutscene, where Kratos gives Atreus a little more detail about gods as you look around.

On the North-Eastern corner of that wall, just back and right of you as you walk into it from the first side chamber, is an R Rune. Hit it with your axe - this is the first of three for a Nornir rune chest that's nearby.

Go out the door to the South back to the main central chamber, grab some wind from the spinning rings, and come back into this room to put it in the trap. There are some enemies to beat first, but nothing too tough.

That triggers another wheel to pop up in the middle instead of the wind trap, and pulling that opens a door to the South-West, to the third side chamber, through another set of traps, and another to the due North which has that Nornir chest at the far end.

Let's get the Nornir rune chest out of the way then. You've already got the R. The N is located in the South-West route to the next chamber. In that trap-filled corridor are some large rectangular blocks of stone that are raised up and down. Look up and right, and when one stone is dropped down you can see the N rune up in the top right above it.

Now turn away from this corridor and go to the one to the North that takes you to the chest. Thise one has sideways-moving masher blocks in it. Stand to the left, and aim for the cog of the second masher when the first one slams to the right.

Now when the first one retracts left, sprint through safely on the right-hand side.

Turn back to face the way you came, and on that first masher that's still moving, you'll see the rune. Recall your axe and throw it at the second masher (the one that's now nearer to you) to freeze it in the open position, then rune forwards and punch the rune to get it, and run back to the chest.

You can now open the Nornir rune chest for another Idunn Apple, and escape the way you entered, by freezing the masher nearer to you and running through when the other one opens.

Now go to that South-Western tunnel towards the third and final room.

Hit the cog on the left of the first vertical masher to freeze it at the top, then stand underneath it, hanging right.

When the second one goes up, run to the right into a little alcove of safety.

Move forwards in there as far as you can go, and when the third masher raises up, you can quickly run out under it to safety.

You're now in the third and final side-room, and there's a puzzle to solve.

Tyr's Vault Water Puzzle solution

Read the runes on the wall ahead with Atreus and he'll give you a bit of lore about the two wolves that chase the sun and moon through the sky.

Repeat the process of exciting the door to the East to the middle chamber, getting the wind from the trap, bringing it back to the wheel to turn it - only this time you can't get the wind right away, you need to climb up the side wall of this central chamber by the gold markings, and defeat the enemies up on the side balcony, before you can get a good angle to grab the wind from there.

Return to the side chamber when you've got the wind and turn the wheel that pops up... and then you're caught in a trap!

This one is time sensitive - you're drowing, basically, and unless you can command Boy to get the symbols on the wall in the right order in time, you'll die.

To get Boy to move the symbols, look in the direction of the lever you want him to pull, and press Square when prompted. Here's the solution, in order of what to pull:

Tyr's Vault Water puzzle solution

1. Middle lever
2. Left lever
3. Middle lever
4. Right lever
5. Left lever
6. Middle lever
7. Right lever

The finished result should look like this, with the moon on the left, disc in the middle, and sun on the right.

In the cutscene, be ready to press Square when prompted, and you're out! Head back to the central chamber to get the Black Rune and finish the job.

Grendels boss fight - how to beat the Grendel of the Ashes and Grendel of the Frost

If only it were that easy eh!

Your reward for solving and surviving all those horrible puzzles and grabbing the rune is a double boss fight, although thankfully it's not the hardest one you've ever had, especially after tackling the Bridge Keeper so recently.

The Grendels are two different elemental trolls. The Grendel of the Ashes is weak to your Leviathan Axe, and the Grendel of the Frost is weak to your chains. All you have to do is switch your damage between the two to take them down. Simple! Sort of.

The main thing to do here is focus on one Grendel at a time. Use whichever weapon you prefer of the two at your disposal and attack the appropriate Grendel - so the Grendel of the Frost if you like using the chains, for instance.

There are a couple of main attacks to watch out for: a spinning attack where they whirl their pillar at you a couple of times, which can be blocked; a sprint forward and slam attack; and the trickiest attack, which has them slam their pillar into the ground to bring up mini pillars from beneath you, that blind you if they connect.

The first two are easily dealt with but the third, with the mini pillars, can be a real pain - keep an eye on both Grendels at all times (normally one's doing this on the edge of the vision when you think you're safe to attack the other) and just keep constantly moving and dodging, and you'll be okay.

Life's a lot easier when one of the two is down, so just burst down the second at this point - but don't get cocky - and when you're done you'll earn another Chaos Flame for upgrading your chains.

Now, you can finally leave, with both the Magic Chisel and the Jotunheim Black Rune. Your next stop is the top of the mountain once more.

Next up: God of War - Return to the Summit