The Valheim Bonemass Boss serves as a serious wake-up call for players. You'll be facing a serious challenge with the third Valheim boss, but it's a battle you can win — even if you're going it alone.
Who is the Third Valheim Boss?
Bonemass is the third Valheim boss. This disgusting creature is a massive blob of ooze that's easily twice as tall as any man and you're going to have a hard time taking him on if you're not careful.
Where to Find the Third Valheim Boss Bonemass
Bonemass can be found in the Swamp biome. 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.
Preparing to Fight the Valheim Bonemass Boss
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.
Step 1: Locate Bonemass Spawn
You can't do the Valheim Bonemass boss fight until you find him. Do that first!
Step 2: Collect a Lot of Stone
Next, you're going to want to start collecting Stone. Two full carts is a good starting point. You might want to build a work camp near the spawner to safely store materials and provide a safe respawn point in case you die.
Step 3: Flatten and Clear the Terrain
The Valheim Bonemass boss fight will give you the Wet debuff and there isn't much you can practically do about it. That said, you're going to want to flatten as much of the land in the surrounding area — you don't want to be slowed down by a pool of water.
It's also wise to remove any trees, stones, or other debris that you can. You can't destroy the gigantic trees in the Swamp, but neither can Bonemass — these will serve as excellent cover from his attacks.
Step 4: Surround the Bonemass Spawner with a Wall
Once the area around the spawner is flat, you're going to want to surround it with a wall. Refer to the above picture — that's a good size for an arena whether you're fighting Bonemass solo or with friends in multiplayer.
Step 5: Build a House for Respawning
You're also going to want to build a small house nearby so you can respawn if you die. Make sure you have enough beds for everyone. It wouldn't be a bad idea to raise the Comfort score so you can have a long Rested buff for the fight, too.
Step 6: Head to the Mountains and Kill Drakes to Craft Frost Arrows
Next, you're going to want to go to the Mountains. No, really.
Bonemass is somewhat weirdly positioned in Valheim's progression — he's the boss of the third biome, but he's most vulnerable to an item you can only get in the fourth biome.
Find a Mountain biome and look for flying dragon creatures called Drakes. Their only attack is to shoot three projectiles at you in rapid succession. These projectiles hit like a truck and can slow you down, but they're pretty easy to avoid.
Ultimately, you're trying to get Freeze Glands from the Drakes. These items will let you craft Frost Arrows, and that is an absolutely essential item for beating Bonemass. I recommend collecting a minimum of 5 Freeze Glands total in order to make 100 Frost Arrows. You should have at least 100 Frost Arrows for every person who wants to participate in the battle.
Step 7: Craft a Blunt Weapon
You're going to need a blunt weapon (such as a mace or a two-handed warhammer) for the same reason that you need Frost Arrows: Bonemass is vulnerable to blunt damage. Don't go into battle intending to use a sword or an axe — you won't do much damage.
Step 8: Craft Poison Resistance Mead, Health Mead, and Tasy Mead
Finally, the last item you'll need is some Mead and Potions. Bonemass does a fair amount of Poison Damage and you should have three or so Poison Resistance Meads per person at the minimum. It's likely you'll only need one, but you want some extras in case you die in the course of battle.
Health Meads, too, are a really good idea. Bonemass hits like a truck, even if you have full Iron armor. Craft Medium Healing Mead if you can manage it. If not, create Minor Healing Mead. Three or so meads per person should be enough for the battle, but having extras can't hurt.
Finally, having some Tasty Mead on hand is always a good idea. While it lowers your Health regeneration by 50%, it massively increases your Stamina regeneration by 300%. It takes 10 seconds for it to do its magic and will fill up your Stamina meter with very little lasting penalties. If you have to use it, jog (don't run) away and let your Stamina get back up to full.
How to Summon Bonemass
Once you've crafted your items and set up the battle area, it's time to summon this big green blob and start the Valheim Bonemass boss fight! You're going to need 10 Withered Bones to make the fight begin.
You can most easily find Withered Bones in Sunken Crypts, either as placed objects, loot in treasure chests, or from the same Muddy Scrap Piles that give you Iron. It's possible to find them without being able to go into the Sunken Crypts (which requires the Swamp Key from the second boss), but it's unlikely that you could easily get the 10 Withered Bones you need in a timely manner.
Place the 10 Withered Bones into that big ol' skull and you're ready to begin!
How to Beat the Valheim Bonemass Boss Solo
The Valheim Bonemass boss fight starts off like most others — 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.
What Are the Bonemass Rewards?
Winning the Valheim Bonemass boss fight will give you two major rewards: access to a new power and the Wishbone.
The Wishbone is an item that can be used to detect underground ore and treasure. You're going to need this to get Silver in the game as it's buried in the Mountain biome. You can also use it to find a small quantity of Iron in the Swamps and treasure chests throughout the world. Keep in mind, however, that the Wishbone occupies the same "utility" equipment slot as the Meginjord — you can't have both equipped at the same time.
What is the Bonemass Power?
Beating Bonemass will also give you the Bonemass Trophy and that item can be used to unlock a new Forsaken Power. This power will give 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!