Valheim Bonemass Boss Guide How To Defeat Bonemass Poison Resistance Mead

Valheim boss guide — How to beat Bonemass and increase poison resistance

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You’ve already taken care of Eikthyr and The Elder. Now that you’ve reached the Swamp biome, it’s time to face Bonemass, the third boss in Valheim‘s campaign. Bonemass also happens to be one of the toughest fights even if you’re well-prepared. Here’s our guide to help you out.

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Note: Valheim is currently an Early Access title. As such, mechanics and content may change in due course. For more information, check out our Valheim guides and features hub.


Valheim boss guide: How to increase poison resistance and defeat Bonemass

Getting started: Bonemass’ location, altar sacrifice, and ideal gear

Bonemass can be summoned in Valheim‘s Swamp biome from its altar (a giant skull). If you haven’t found its location yet, then some of the Sunken Crypts in the region might have a runestone that would mark the boss’ location.

Also found in Sunken Crypts are icky blockages called muddy scrap piles. Destroying these grants you iron scraps and Withered Bones. For iron scraps, you’ll have to smelt these into iron bars which, in turn, can be forged into weapons and armor. One particular weapon you’ll want to make is the Iron Mace (20x iron, 4x wood, and 3x leather scraps) since this will be useful for the encounter.

As for Withered Bones, you need 10 of these to offer to Bonemass’ giant skull altar. Doing so will spawn your foe, a massive green blob akin to Slimer from Ghostbusters.

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Bonemass’ attacks and abilities

Like the previous two bosses, Bonemass has a regular melee swipe that can be dodged or blocked. It also has two notable abilities:

  • Ooze Throw – A couple of oozes will be thrown near you, and these will turn into hostile mobs. It’s a bit overkill considering that your surroundings will already have several draugrs, leeches, skeletons, surtlings, and other oozes.
  • Poison Breath – This breath attack explodes into a poisonous mist.

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What makes Bonemass difficult?

There are three reasons why the Bonemass encounter tends to be tougher compared to anything you’ve experienced so far in Valheim. Firstly, this slimeball is heavily resistant to piercing damage (including most arrow types). It’s weak to frost arrows, but you likely won’t be able to acquire a lot of these until you reach the Mountains biome.

Owing to the above, you’re going to have to do the dirty work in melee range. That’s why your best option is the Iron Mace (or perhaps other blunt melee weapons). It also implies that you need to do DPS, all while avoiding its attacks and the pack of mobs that’ll surround you.

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Moreover, the poison status effect is extremely deadly. At close range, you’re likely to be afflicted with this due to its Poison Breath or the globules from other oozes and blobs. Not only will you lose health each second, but you also won’t be able to regenerate enough to offset these ticks. This is why you’ll need a few poison resistance mead items with you (10x honey, 10x coal, 5x thistle, and 1x neck tail). Most of these materials can be easily obtained, but honey has to be farmed from beehives.

When you drink a poison resistance mead, the damage-over-time (DOT) effect is slightly nullified to around 1.5 HP per second. Simply get in to wail away at Bonemass, dodge its swing, and don’t stay in the Poison Breath’s lingering area-of-effect.

Just remember that the poison resistance mead’s buff lasts for 10 minutes. You can dip in and out when you feel that things are getting too hectic, then drink another one if the previous effect’s about to wear off. Hey, it’s a battle of attrition, but you’ll slowly be able to whittle Bonemass down while being careful of pesky mobs that cross your path.

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Bonemass’ loot and Forsaken Power

After defeating Bonemass, you’ll get the following drops:

  • Wishbone – This is an accessory that you can equip. It lets you detect hidden items underground such as silver deposits in the Mountains biome.
  • Bonemass trophy – Return to the summoning stone circle and hang this on the matching pillar. You’ll gain Bonemass’ Forsaken Power, providing a temporary buff that greatly boosts your resistance to physical damage (i.e., blunt, piercing, and slashing weapons).

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Jason Rodriguez
Jason Rodriguez is a guides writer. Most of his work can be found on PC Invasion (around 3,400+ published articles). He's also written for IGN, GameSpot, Polygon, TechRaptor, Gameskinny, and more. He's also one of only five games journalists from the Philippines. Just kidding. There are definitely more around, but he doesn't know anyone. Mabuhay!