Originally posted by wingerman:

health mead, poison resist, and maxed out iron mace, and iron gear
blunt damage is key.

Exactly this ! The secondary attack hits for around 200 dmg, and you can land 2-3 hits between his attacks, it's much faster than the arrows, which deal like 15-20 dmg only.
If you have high blocking skill, you can parry his attack effectively, with the right timing (he hits at the same speed as a troll, if it can help.), otherwise a roll always works.
Also bring good food to raise your hp and stamina, sausages are great (easy to farm materials from the swamp) and black soup is pretty good too.

I find Bonemass much easier than Moder or The Elder. Flatten the ground around his statue. Attack with blunt. Always have poison resistance on. When health or stamina gets too low, just walk around the statue. That's all there is to it: walk around his altar in a circle. Bonemass follows at about the same speed, like in a slapstick movie. Kill his blobs on your way. When you have recovered enough (through time and potions), attack again. Rinse and repeat. Hard to lose that way, actually.

Best foods for that battle are : serpent stew , serpent cooked meat and turnip stew
Iron set and iron mace , iron buckler

Originally posted by Brew:

I don't think you'll have frost arrows at this point, unless you've skipped ahead. That requires stuff from the next biome. I doubt the encounter is designed to require that. May as well recommend black steel too, while you're at it...

I too found arrows ineffective. Had much better luck with my mace.

many people skip bonemass and go to explore mountains and plains first. I did it to get better food and tame wolves and loxes. I feel pretty comfortable in plains with maxed root armor set and good food.

Iron Sledge, Staghammer (might need multiple), poison resistance, and the altar.

Iron mace, upgraded to level 4, and poison resistance mead. Plus the best foods you have access to.

The mace absolutely wrecks him; the last time I fought him the battle took a maybe five minutes. Mace secondary attack is

If you have trouble surviving his melee swipe. Take the iron tower shield. It literally makes you the tower.

health mead, poison resist, and maxed out iron mace, and iron gear
blunt damage is key.

Originally posted by TooTall1:

Originally posted by 48kg kid Aleksiben:

Frost arrows

Shot from a perch you have already built well above his head, near his spawn point, in a tree that is indestructible. Get 250 frost arrows to be on the safe side. Youtube has videos on either method.

This method doesnt work anymore. Bonemass will flee and heal pretty fast. You have to be at the ground, or at least within the reach to prevent him from fleeing.

It can work, but you must be lucky to spawn him in the trees. https://steamcommunity.com/sharedfiles/filedetails/?id=2721254376

I don't think you'll have frost arrows at this point, unless you've skipped ahead. That requires stuff from the next biome. I doubt the encounter is designed to require that. May as well recommend black steel too, while you're at it...

I too found arrows ineffective. Had much better luck with my mace.

Frost arrows

Iron mace and armor. If you must.

Originally posted by Scoob454:

Iron mace and armor. If you must.

And a poison potion. While he is drowning you in poison, wail on him. When he swings on you parry or dodge. When he pops out adds, quickly kill them then back to job one. Stamina and health pots at the ready.

Originally posted by 48kg kid Aleksiben:

Frost arrows

Shot from a perch you have already built well above his head, near his spawn point, in a tree that is indestructible. Get 250 frost arrows to be on the safe side. Youtube has videos on either method.

Mace and Armour... (Poison Resistance Potions)
Every time new ads spawn pick them off first and then go back to attack Bonemass..
Dodge his heavy attacks.. You can also block these attacks. (Round shield)
With Poison Resistance you don't need to dodge his AOE Poison attack, but it's better if you can.

I don't suggest using arrows of any kind, they deal low damage.

The fight can take up to 20min depending on your gear and what level your skills are.
He's fairy easy to beat.