Valheim Bonemass Boss Fight Guide

Last Update: April 16, 2023 10:54 AM /


Valheim Bonemass Guide cover

Our Valheim Bonemass Boss Fight guide tells you where to find the game's third boss, how to prepare for the fight, and how to beat him!

Where to Find the Bonemass Boss in Valheim

Bonemass can be found in the Swamp Biome in Valheim. Finding your first Swamp can be a little tricky and the biome itself is wrought with peril -- especially if you go in under-geared. It's strongly recommended that you go in with an ample supply of food and fully-upgraded Bronze tools and weapons at the minimum.

As with most bosses, you can try to find a Runestone that will put one of the Bonemass locations on your map. His spawner is a gigantic skull, though, and it's not too difficult to spot it when you're running through a Swamp; you may very well find Bonemass' spawner before you find a stone that tells you where he is!

If you're still having trouble, you can typically find Bonemass Runestones within some of the stone towers in the Swamp. Spend some time running around in the Swamps and you'll come across one eventually.

How to Unlock the Bonemass Boss in Valheim

Here's how to unlock the Bonemass Boss in Valheim:

  1. Defeat The Elder Boss
  2. Travel to the Swamp Biome. Make sure to take a Swamp Key with you.
  3. Use the Swamp Key to explore Sunken Crypts and collect 10 Withered Bones. You'll likely have to explore multiple Crypts to get enough.
  4. While exploring Sunken Crypts, search for the Bonemass Vegvisir to find his location.
  5. Take the 10 Withered Bones to the Bonemass Altar to summon him.

Valheim Bonemass Guide castle

How to Prepare for the Valheim Bonemass Boss Fight

Fighting Eikthyr and the Elder are a cakewalk in comparison to this fight against Bonemass. Summoning him without proper preparation will likely result in your death, and don't forget -- bosses don't despawn in Valheim. Fail to kill him and he'll be hanging around forever until you actually defeat him.

What is the Bonemass Weakness?

Bonemass' main weaknesses are Blunt damage and Frost. It's easy enough to bring a Mace to the battle, but I strongly recommend preparing some Frost Arrows in advance.

Unfortunately, Frost Arrows can only be acquired by killing Drakes in the Mountains Biome. That means you'll have to do a bit of sequence breaking and travel into the fourth Biome in order to have an easier job of defeating the boss of the third Biome.

Making the trip to the Mountains is worth it, though. The extra damage afforded by Frost Arrows can make taking down Bonemass much easier than you'd expect -- and fighting him from range is much safer, too.

How to Summon the Bonemass Boss in Valheim

You can summon the Bonemass Boss in Valheim by placing 10 Withered Bones on his Altar.

Valheim Bonemass Guide solo

How to Beat the Valheim Bonemass Boss Solo

The Bonemass Boss fight starts off like most other Boss fights in Valheim -- you'll see a bunch of energy balls start to come together as some awesome metal music kicks off. This will let you know where the boss is going to spawn into the world. You're going to want to be as far away from Bonemass as possible at the beginning.

Bonemass has three attacks:

  • Melee swipe - Bonemass will swing his arm in a wide arc at you. This is telegraphed very heavily and you do not want to be hit by this attack. If you can't avoid it, block or parry it. Either way, immediately get out of range if you take a hit.
  • Summon monsters - Bonemass will grab a piece of gunk off of his body and throw it in your general direction. Once this blob lands, it can spawn Skeletons, Blobs, or nothing at all. Kill these adds immediately before continuing to do damage to Bonemass.
  • Poison Cloud - Bonemass will vomit on the ground and create a cloud of poisonous gas around him that's about twice as wide as his body. This cloud sticks around for a while, so you don't want to be in the area at all.

In my research for this fight, I saw a lot of people advising that you get a blunt weapon and go in for Melee damage. I do not recommend doing this in single-player -- it's nigh-suicidal. Instead, your focus should be on shooting Bonemass from range with Frost Arrows.

Keep Bonemass at a distance, firing Frost Arrows as you go. Immediately take on any Skeletons or Blobs that he spawns so that you can keep your focus on Bonemass. Eventually, you'll whittle his health down to zero and you're done!

Should you die, you'll be really happy that you build a base nearby to respawn. The only real way to fail is to run out of Frost Arrows. That's the best way to do damage — if you run out, it's probably a good idea to retreat, craft more items that you need, and start the fight over. Bonemass won't despawn until he's dead.

How to Beat the Valheim Bonemass Boss in Multiplayer

Not much changes for a Bonemass multiplayer fight with the exception of his health and damage increasing due to Valheim's difficulty scaling system. Although his health is higher, you may actually be able to defeat him quicker, believe it or not.

Bonemass can only focus on one player at a time. That gives every other player the opportunity to hit him from behind with a melee blunt weapon. A fully-upgraded Iron mace or warhammer will do more damage than Frost Arrows, but you risk taking a lot of damage.

You can certainly try to dip in and hit him with melee when he's focused on another player. That said, it's safer (and only a little slower) to pelt him from range with Frost Arrows.

Valheim Bonemass Guide Silver

What Are the Bonemass Boss Drops in Valheim?

Winning the Valheim Bonemass boss fight will give you the Bonemass Trophy and the Wishbone. The Wishbone is an item that can detect items hidden underground and is essential for finding Silver in the Mountains Biome.

What is the Bonemass Power?

The Bonemass Power gives you a crazy amount of physical resistance once it's activated. If you're going into a situation where you think you'll be hit a lot, it's not a bad choice to take this power with you!

We're all done with the Valheim Bonemass Boss Fight Guide, but there's plenty more to explore in our other guides below!

Have a tip, or want to point out something we missed? Leave a Comment or e-mail us at

A photograph of TechRaptor Senior Writer Robert N. Adams.
| Senior Writer

One of my earliest memories is playing Super Mario Bros. on the Nintendo Entertainment System. I've had a controller in my hand since I was 4 and I… More about Robert N

More Info About This Game
Learn More About Valheim
Game Page Valheim
Iron Gate
Release Date
February 2, 2021 (Calendar)
Survival, RPG, Indie
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