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Valheim Bonemass guide: how to summon and defeat Bonemass

How to find, summon, and defeat Bonemass

Want to know where to find and defeat Bonemass in Valheim? One of the legendary Forsaken that you have been sent to defeat by Odin himself, Bonemass is the third perilous boss in Valheim. You'll need to know more than just the beginning tips & tricks to tackle Bonemass.

Our Valheim Bonemass boss fight guide will explain exactly how to locate, summon, and kill Bonemass. We'll also walk you through the unique rewards you'll earn after slaying it.


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Valheim Bonemass boss location

Bonemass, like the other Valheim bosses, does not appear somewhere in the world at the start of a game. Instead, it must be summoned at a Bonemass Mystical Altar, of which there are several scattered across each Valheim map. To find the nearest such Mystical Altar, you'll need to find and interact with a Vegvisir - a glowing red runestone which will transcribe the Altar location on your map.

Bonemass resides in the Swamp biomes, so you'll need to look for runestones in Swamps - specifically in the Sunken Crypts found in certain Swamp biomes. You'll need to have defeated the previous boss, The Elder, in order to gain access to these Sunken Crypts.

Once it's marked on the map, travel there to find Bonemass's Mystical Altar - a giant skull sticking out of the ground.


How to summon Bonemass in Valheim

Like all bosses, to summon Bonemass you'll need to make an offering at its Mystical Altar. In this case, you need to place 10 Withered Bones on the Altar to summon the boss into the world.

Withered Bones can be found in exactly the same places as Iron: in Muddy Scrap Piles and in Sunken Crypts. You may need to scout more than one Sunken Crypt in order to find 10 Withered Bones, but once you have them you should return to the Bonemass Altar. Place the Bones in your hotbar and press the corresponding number key with your cursor placed over the Altar to summon Bonemass and begin the boss fight.

A Valheim screenshot of Bonemass, the third boss, standing in a cloud of its own green poisonous gas.

Valheim Bonemass boss fight guide

If you're not well-prepared for this boss fight then Bonemass will rip right through you, so I'd recommend preparing yourself by finding and smelting enough Iron to make an Iron Mace, which is particularly useful for this fight because Bonemass is weak against blunt attacks.

You'll also want plenty of Health and Stamina, so I'd recommend eating good-quality Cauldron-tier foods in order to reach around 150 max Health. Take some Poison resistance mead as well, because that extra resistance will certainly be useful for this fight. As for armor, the stronger the better. You'll ideally have moved on from Leather or Troll Hide at this point and will be wearing Bronze or Iron armor.

As for the boss fight itself, Bonemass is a great big blob that loves to spawn enemies and spew poison. If you get close it'll take a swipe at you which you should be sure to block or evade, but really it's the poison that will kill you if anything.

The first poison attack occurs when Bonemass clutches its stomach and rears its head. A large cloud will appear around the boss, poisoning any player caught inside. The other poison attack occurs when Bonemass throws a clump of itself at the ground nearby. This clump will spread poison and also summon Blobs and Skeletons where it lands. Because of this, I'd recommend you keep Stagbreaker on your hotbar as well as your Iron Mace, because Stagbreaker is great for quickly dealing with clumped up groups of smaller enemies.

With good gear and Health - and of course, the Poison resistance mead - the poison shouldn't be too punishing as long as you don't stand in it for too long. Keep clubbing away at Bonemass whenever you aren't in danger of being poisoned, and with a bit of perseverance you'll defeat it and reap the following rewards.


Bonemass Forsaken Power & loot drops

After defeating Bonemass, head over to its remains to pick up what it drops: a Bonemass Trophy to unlock its Forsaken Power, and the Wishbone.

Return the Trophy to the circle of stones at spawn and place it on the third stone's hook, then interact with the stone to gain Valheim's third Forsaken Power. This power grants you resistance to physical (blunt/slash/pierce) damage, meaning you take less damage from attacks of these types.

As for the Wishbone, this powerful tool can be used to find buried treasure. With the Wishbone equipped (it is equipped in a special Armor slot so you don't need it on your hotbar) you will see green sparks appear around your character if something is buried nearby. Follow the sparks and dig with your Pickaxe to find treasure, including rare Silver Ore deposits.


And with that, we'll conclude this Valheim Bonemass boss guide. Hopefully you've learned everything you need to know about finding and defeating this dangerously gaseous foe. For more information on the other bosses in the game, check out our Valheim bosses guide.

About the Author

Ollie Toms avatar

Ollie Toms

Guides Editor

Ollie is known round these parts for having just about the deepest voice in existence. Some say he used to be pretty darn good at Rocket League, but he has since sacrificed that accolade in order to become passably decent at Apex Legends. His favourite pastimes include playing piano covers of his favourite game soundtracks, and burying his face in the warm fur of his two cats.

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