Bonemass is the third Forsaken boss in Valheim. With the right food, armor, weapon, and strategy, however, the fight becomes much more manageable. The key is not raw damage alone, but controlling the arena and managing your stamina carefully.
Bonemass is found in the Swamp biome. To locate its summoning altar, explore Sunken Crypts and look for a Vegvisir that reveals the boss location. You need 10 Withered Bones to summon Bonemass. These can be found while exploring the Swamp, including inside Sunken Crypts.
Before starting the fight, prepare the area around the altar. Clear nearby enemies and use a Hoe to make the ground easier to move across. This is important because uneven Swamp terrain and water can make escaping poison attacks much harder.
Best Gear for Bonemass
The most important weapon for this battle is an Iron Mace. Bonemass is weak to blunt damage, making a mace far more effective than swords or most ranged weapons. Upgrade your Iron Mace as much as possible before the fight.
Full Iron armor is also a strong choice because it gives you better protection against Bonemass and the enemies it summons. Bring a reliable shield as well.
Your food should provide plenty of health and stamina. Sausages, Black Soup, Turnip Stew, or other strong Swamp-era meals can give you the extra health and stamina needed for a long battle.
Do Not Forget Poison Resistance Mead
Poison Resistance Mead is arguably the most important item in this fight. Bonemass uses powerful poison attacks, and staying exposed to them can quickly drain your health.
Drink the mead before engaging Bonemass so its resistance is already active. Carry several doses because the fight can last longer than expected.
Also bring healing and stamina mead. Having emergency healing available can save a run when you make a mistake.
How to Fight Bonemass
Bonemass has three main attacks you need to understand. Its large melee swing can deal heavy damage at close range. You can block or dodge it, then step in for a few mace attacks.
The second attack is a thrown blob. Bonemass pulls material from its body and throws it, creating additional enemies such as Blobs and Skeletons. Do not allow these enemies to surround you. Clear them when they become dangerous, then return your attention to the boss.
Its most dangerous attack is the poison cloud. Bonemass leans back before releasing a large green cloud around itself. When you see this animation, immediately move away. The cloud cannot simply be blocked, so creating distance is the safest response.
Use Short Attack Windows
Do not try to stand beside Bonemass and continuously swing your weapon. This can leave you without enough stamina to dodge its attacks or escape the poison cloud.
Instead, stay close enough to bait its melee attack. Once the attack finishes, move in and land a few Iron Mace hits. Then back away and recover your stamina. Repeat this process throughout the fight.
If Bonemass throws a blob, decide whether the summoned enemies need to be killed immediately. Ignoring them can become dangerous if several Skeletons and Blobs accumulate.
What You Get for Defeating Bonemass
Defeating Bonemass rewards you with the Bonemass Trophy and Wishbone. The Wishbone is especially useful because it helps detect buried objects, including Silver in the Mountains.
Bonemass also provides a Forsaken Power that improves your resistance to physical damage and makes blocking much less demanding on your stamina. This can be extremely useful during difficult encounters later in Valheim.
