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