You have beaten The Elder, his Swamp Key is in your inventory, and the next spot on the Sacrificial Stones belongs to Bonemass. The fight comes down to three things: poison you cannot block, a crowd of Skeletons and Blobs, and weapons he barely notices. Here is where to find him, what to bring and how to win. For all eight bosses in one list, see our Valheim bosses in order guide.
Quick answer: Bonemass is the third boss in Valheim. His altar stands in the Swamp, and a Vegvisir inside a Sunken Crypt (opened with The Elder's Swamp Key) marks it on your map. You summon him with 10 Withered Bones, mined from Muddy Scrap Piles in those crypts. He has 5,000 health, takes extra damage from blunt and frost, barely feels pierce or fire, and is immune to poison. Bring an Iron Mace or Iron Sledge, Poison Resistance Mead that you drink before he hits you, healing meads and your best Swamp food, and kill his Skeletons and Blobs as they land. He drops a Wishbone, which finds silver in the Mountains.
Where to Find Bonemass in Valheim
Bonemass lives at a stone altar in the Swamp, with a runestone beside it that reads "COOK THEIR REMAINS". Each world has five of these altars, 3,000 metres apart and at least 2,000 metres from the world centre (Forsaken Altars). A glowing Vegvisir runestone in a Sunken Crypt, or sometimes in a Swamp ruin, marks the nearest one on your map (Bonemass).
Sunken Crypts are the stone dungeons with an iron gate in the Swamp. The Swamp Key from The Elder opens them and is never used up (Swamp Key). Inside wait Draugr, Draugr Elites and poisonous Blobs, so bring poison protection for the crypts too (Sunken Crypts).
How to Summon Bonemass: 10 Withered Bones
Withered Bones come from Muddy Scrap Piles inside Sunken Crypts and from chests in the Swamp (Withered Bone). A pile inside a crypt has 30 segments, and each segment has a 2.86% chance to drop a bone, so a pile gives 0.86 bones on average (Muddy Scrap Pile). Plan on clearing about a dozen piles. The same piles give the Scrap Iron for your gear.
Two details save trips:
- Withered Bones go through a regular portal, Scrap Iron does not. Send the bones home by portal and sail the iron back.
- Once you place the bones, Bonemass appears and stays until he is dead (Forsaken Altars). Summon him only when you are ready. Another 10 bones bring him back for a rematch.
Bonemass Attacks and How to Avoid Them
Poison cloud. He leans backwards, then vomits ooze that poisons everything within 9 metres for 130 poison damage (Bonemass). The cloud stays for 15 seconds and keeps refreshing your poison while you stand in it. You cannot block or dodge it. He uses it when someone is within 15 metres, at most once every 30 seconds. The cloud does not reach far behind him, so his back is a safe spot that is still in reach of your weapon. If you are in front, start running the moment he leans back: running gets you clear faster than rolling and costs less stamina (Boss strategies).
Punch. A swipe in front of him for up to 80 blunt and 50 poison damage, every 7 seconds, within 8 metres. A normal block will likely stagger you and let the rest through. Roll through it, sprint out of range or parry it. He is immune to stagger, so a parry stops the damage but does not knock him off balance.
Throw. Every 50 seconds he throws a glob from his armpit that spawns four Skeletons or Blobs where it lands, with up to eight of each alive at once. The animation is slow, which gives you free hits or time to meet the adds as they land. Ignore them and they can overwhelm you.
Rain. Bonemass brings rain, so you stay Wet the whole fight. Wet cuts health regeneration by 25% and stamina regeneration by 15%, and you cannot get Rested while Wet (Wet). Get Rested before you summon him.
What Bonemass Is Weak To
| Damage type | Bonemass is | Damage he takes |
|---|---|---|
| Blunt | Weak | 150% |
| Frost | Weak | 150% |
| Slash | Resistant | 50% |
| Pierce | Very resistant | 25% |
| Fire | Very resistant | 25% |
| Poison | Immune | 0% |
Resistances from the wiki's Bonemass page, percentages from its Resistance table. In practice: leave the sword, spear, fire arrows and poison at home and bring a club. His Skeletons are weak to blunt too, so one club covers the whole fight.
Best Weapons for Bonemass
| Weapon | Damage | Crafting | Use it for |
|---|---|---|---|
| Iron Mace | 55 blunt | Forge level 2: 20 Iron, 4 Wood, 3 Leather Scraps | Steady damage on Bonemass, with a shield |
| Iron Sledge | 55 blunt, everything within 4 m | Forge level 2: 30 Iron, 10 Ancient Bark, 4 Ymir Flesh, 1 Draugr Elite Trophy | Clearing Skeletons and Blobs as they land |
| Stagbreaker | 20 blunt, 5 pierce, within 4 m | Workbench level 2: 20 Corewood, 5 Deer Trophies, 2 Leather Scraps | Cheap crowd control before you have iron |
| Frostner | 35 blunt, 40 frost, 20 spirit | Forge level 3: 30 Silver, 10 Ancient Bark, 5 Ymir Flesh, 5 Freeze Glands | Rematches, once you have silver |
| Frost Arrows | 26 pierce, 52 frost | Workbench level 4: 8 Wood, 4 Obsidian, 2 Feathers, 1 Freeze Gland for 20 | Groups that prefer bows |
The Iron Mace is the easy pick: its main cost is iron from the crypts, and its slower secondary attack hits for 2.5 times the damage. The Iron Sledge does the same damage to everything around you, which is what you want when the Skeletons land. Haldor sells its Ymir Flesh once The Elder is dead, a change Iron Gate made in patch 0.213.4, and the Draugr Elite Trophy drops in the same crypts.
The wiki calls Frostner the ideal weapon because it hits both weaknesses, but silver is hard to find before you own the Wishbone that Bonemass drops. Frost Arrows need Obsidian and Freeze Glands from the Mountains. Treat both as rematch gear.
Armour, Meads and Food to Bring
Poison Resistance Mead is the item the fight is balanced around. For 10 minutes you take a quarter of the poison damage. Make the base at the Mead Ketill from 10 Honey, 5 Thistle, 1 Neck Tail and 10 Coal and ferment it into six meads. It only works on poison that lands while it is active, so drinking it after a hit does nothing for that poison (Poison Resistance Mead, Poison). Drink it right before you place the bones.
Root Mask. It halves poison damage and never wears off. It does not add up with the mead, because only the strongest resistance counts, but it covers you if the mead runs out (Root Set, Resistance). Its Roots drop from Abominations, the walking trees of the Swamp.
Armour and shield. Iron armour gives 14 armour per piece (Iron Armor), and you can wear the Root Mask with the Iron chest and legs. The Banded Shield (Forge level 2, 10 Finewood, 8 Iron) has 42 block armour and can parry (Banded Shield). Our armour sets guide compares the Swamp sets.
Healing. A Medium Healing Mead restores 75 health over 10 seconds, with a 2 minute cooldown. Its base takes 10 Honey, 4 Bloodbags, 10 Raspberries and 1 Dandelion (Medium Healing Mead). Bring several.
Food. Poison eats health, so eat two health dishes and one stamina dish. For health: Serpent Stew (80 health, 26 stamina) if you have killed a Serpent, Sausages (55/18) or Black Soup (50/17). For stamina: Turnip Stew (18/55). Figures from the wiki pages for Serpent Stew, Sausages, Black Soup and Turnip Stew; our Valheim food guide has every tier.
Forsaken power. Eikthyr's power cuts stamina use for running and jumping by 60%, which helps you escape the cloud. The Elder's adds 30% health regeneration. Each lasts 5 minutes, and all powers share a 20 minute cooldown (Forsaken power).
A Fight Plan That Works
- Set up camp. Build a small roofed shelter with a fire near the altar, dry off and get Rested. Place a portal home if your world allows it: with the No boss portals world setting, portals do not work while a boss is active (World Modifiers).
- Prepare the ground. Level the ground around the altar with a Hoe. Firm footing makes dodging easier, and the wiki notes it keeps Leeches out of the fight.
- Eat, drink, summon. Eat three foods, use your Forsaken power, drink the Poison Resistance Mead, then place the 10 bones.
- Stay at his side or back. Hit him with the mace and stay out of the arc in front of him. When he leans back, step behind him or sprint more than 9 metres away.
- Kill the adds first. When the glob lands, kill the Skeletons and Blobs, then go back to Bonemass.
- Heal early. Drink a healing mead as soon as poison takes a real chunk of health. When the resistance mead is about to run out, back off and drink the next one.
For solo players the wiki describes a safer route: climb onto his altar from the rear and swing a two-handed club from up there. The knockback throws spawns off the altar and his attacks cannot reach you, though you will likely still get poisoned (Boss strategies).
Fighting Bonemass With Friends on a Server
For every extra player within 100 metres, creatures get 30% more effective health and deal 4% more damage, and that scaling stops growing at five players (Multiplayer). What works for a group:
- Spread out, so the poison cloud only hits the player he is chasing.
- Give most players the job of killing the adds as they land. With up to eight Skeletons and eight Blobs alive, they are the real danger.
- Three or more archers can still bring him down with plain arrows, as long as they switch to clubs for the adds (Boss strategies).
- A Forsaken power reaches everyone within 10 metres, so four players can take turns and keep one running.
If the fight is too hard for your group, the server admin can lower the difficulty with the launch option -modifier combat easy (other values: veryeasy, hard, veryhard) from Iron Gate's guide to dedicated servers.
A dedicated server also keeps the world online when your usual host is not playing. Our Valheim server hosting runs Valheim 1.0 for groups of up to 10 players, Windows (Steam) only.
What Bonemass Drops: the Wishbone and His Forsaken Power
Bonemass drops his trophy and a Wishbone (Bonemass).
Wishbone. An accessory that finds buried secrets. Equip it and it starts to ding about 20 metres from something buried, faster and higher as you get closer. Dig where it is strongest for Silver veins in the Mountains, Muddy Scrap Piles in the Swamp, treasure in the Meadows or chests in the Deep North. It shares a slot with Megingjord and the Wisplight (Wishbone).
His Forsaken power. Hang the trophy at the Sacrificial Stones. Since patch 0.221.4, Call To Arms, Iron Gate lists the power as "25% resistance VS pierce, slash, and blunt damage, 100% reduced block stamina usage, 5 stamina on return per block" (patch notes). It lasts 5 minutes and covers allies within 10 metres. Iron Gate's notes since then, through the 1.0 launch up to patch 1.0.21 on 28 October 2026, list no change to Bonemass.
What changes in your world. After Bonemass, Skeletons spawn at night in the Meadows, Black Forest, Swamp, Mountains and Plains, and new raids start. Two of them bring flying enemies that ignore base walls and attack tamed animals, so the wiki advises an indoor barn for your boars before the fight (Bonemass).
Next is Moder in the Mountains: wear the Wishbone to find silver and bring frost protection. Our Moder guide covers that fight, and the Valheim progression guide shows the full order.
FAQ
Where is Bonemass in Valheim? At an altar in the Swamp. Activate a Vegvisir in a Sunken Crypt or Swamp ruin and the nearest of his five altars appears on your map.
How many Withered Bones do you need to summon Bonemass? Ten. Muddy Scrap Piles in Sunken Crypts give 0.86 bones each on average, so expect to clear about a dozen.
What is Bonemass weak to? Blunt and frost. He resists slash, is very resistant to pierce and fire, and is immune to poison, so an Iron Mace or Iron Sledge is the usual choice.
Can you beat Bonemass with a bow? Alone it is slow, because he takes a quarter of pierce damage. Frost Arrows work better but need Mountain materials. A group of three or more archers can do it with normal arrows.
What does Bonemass drop in Valheim? His trophy, which gives his Forsaken power at the Sacrificial Stones, and a Wishbone, which finds buried silver, scrap piles and treasure.
Can you fight Bonemass again? Yes. Place another 10 Withered Bones on his altar and he comes back, as often as you like.
Sources
All opened on 2 November 2026:
- Iron Gate on Steam: Patch 0.221.4, Call To Arms (9 September 2025), Patch 0.213.4 (7 February 2023), Valheim 1.0 launch notes (9 September 2026), Patch 1.0.21 (28 October 2026)
- Iron Gate: A Guide to Dedicated Servers
- Valheim Wiki: Bonemass, Boss strategies, Forsaken Altars, Sunken Crypts, Swamp Key, Withered Bone, Muddy Scrap Pile, Wishbone, Forsaken power, Resistance, Poison, Wet, Poison Resistance Mead, Medium Healing Mead, Root Set, Iron Armor, Banded Shield, Iron Mace, Iron Sledge, Stagbreaker, Frostner, Frost Arrow, Ymir Flesh, Serpent Stew, Sausages, Black Soup, Turnip Stew, Abomination, Multiplayer, World Modifiers
- Valheim Wiki on Fandom, the wiki linked from valheim.com: Bonemass (same health, attacks and resistances)