Here is the full list of all 11 Unsung Warriors - there are Prologue achievements.
Collect 500 gold.
Destroy the skeleton boss by using only your fists as a weapon.
Drop a box on an enemy
Find the Cavern of Names inside the crypt.
Destroy an enemy with a bomb.
Destroy an enemy with an oil lamp.
Defeat the skeleton boss.
Destroy an enemy by stabbing him in the back.
Save the lost brother from the crypt.
Destroy an enemy by pushing him under a crushing block.
Destroy an enemy by smashing him into spikes.