Summon and defeat Bone Mass, the third boss in Valheim

Rejoindre le Discord

With this guide, you will know how to summon and defeat Bone Mass, the third boss in Valheim.

Did Eikthyr or the Elder give you a hard time? Bone Mass is even more difficult than its predecessors.

Invoquer et Vaincre Masse d'os, le troisième boss de Valheim


  • Bone Mass Trophy
  • Fallen Power
  • Bréchet

Find Bone Mass

To summon and defeat Bone Mass, the third boss of Valheim, you must discover its location by exploring the crypts buried in the swamp area. You will find a rune that will reveal the location of Mass d'Os, he is still in the “swamps” biome.


Invoquer et Vaincre Masse d'os, le troisième boss de Valheim

As mentioned before, this fight is going to be much more difficult than the previous ones. We advise you to prepare healing potions but also poison resistance potions.

Bone Mass is very sensitive to blunt damage, so it is advisable to make an iron mass.

Summon Mass of Bones

Invoquer et Vaincre Masse d'os, le troisième boss de Valheim

You can summon Bone Mass, the third boss in Valheim by collecting 10 atrophied bones. To recover atrophied bones, you must destroy the various heaps of mud that are in the buried crypts.

Finally, to make Bone Mass appear, you must place the bones collected in the skeleton's mouth.

Bone Mass Attacks

To defend itself, Bone Mass has 4 attacks.

In melee, Bone Mass will slap his arms, inflicting heavy physical damage that applies poison.

From a distance, Bone Mass will rain poison into the combat zone, which will apply the wet effect but also the poison effect.

He will also vomit poison in front of him, which will have the effect of applying the poison effect to you.

The biggest danger will come from the groups of blobs that he will summon from a distance. These blogs are going to poison you.

Bone Mass can also summon skeletons that inflict physical damage on them.

Defeat Bone Mass

As you will have understood, Bone Mass will essentially inflict attacks on you that will poison you. Poison resistance potions will therefore be during this fight, do not hesitate to use one before starting the fight.

It is recommended that you give the boss a few hits and then walk away when he spits green smoke or uses his attack that causes acid rain to fall.

When he summons his blobs or the skeletons, try to get rid of them as quickly as possible.

Although the fight is likely to be very long, if you manage to dodge its poison as much as possible, you should be able to overcome this third boss.

Once you defeat Bone Mass, you will receive the Bréchet, the Bone Mass trophy, and a new fallen power. This new power will allow you to reduce all physical damage taken, which is very useful for making a difference during a big melee.

To benefit from this power, you must hang the Bone Mass trophy at the level of the stone circle.

Want to know more? Watch the tutorial by Morrighn4n on YouTube!

Discover our Valheim offer & join us on our Discord !