Here is the full list of all 23 Iron Danger achievements.
Hunt down and slay all of the trolls in Bleakshore.
Take a troll into the Northlander camp.
You successfully completed Iron Danger. Congratulations!
Destroy all three gates leading into the Northlander camp.
You found the fifth Shard. Your enemies tremble before you.
You put the Tyrannogrouse out of its misery.
You healed the wounded Tyrannogrouse.
Eat roosterfish roasted over campfire.
You found the fourth Shard, and it eases your pain.
Collect 30 mushrooms.
Kill the alpha Roosterfish in the temple under Rimfeden.
Die 100 times.
Blow yourself up by shooting explosive arrow while on fire.
Grow stealth grass 20 times.
You found the third Shard, and it makes you shiver.
Defeat 100 enemies.
Use Earthquake while boosted by fire.
Kill 30 keyus.
You found the second Shard and feel the nature's call.
Collect 20 berries.
Find and read the recipe in Kalevala.
You found the fabled Healer of Brumehead.
You found the first Shard poking through your chest.