Here is the full list of all 38 Souldiers achievements.
Complete the game as a Scout.
Complete the game as all three classes.
Unlock all skills.
Complete the game as a Caster.
Finish a game on Game+ mode.
Reveal 100% of every map.
Complete the Bestiary in your Encyclopaedia.
Upgrade your protection the highest level.
Upgrade your weapon to the highest level.
Collect all secondary weapons.
Find all of the hidden rooms.
Defeat 5,000 enemies.
Destroy 10,000 environmental objects.
Defeat Beigon on Soldier or Warrior mode.
Collect all Dark Crystals.
Complete the game as an Archer.
Complete the game on Warrior mode.
Complete all side quests.
Defeat Agginox on Soldier or Warrior mode.
Defeat all Dark Warriors.
Defeat Galath a second time.
Defeat Ratatosk on Soldier or Warrior mode.
Discover 50 hidden rooms.
Destroy 3,000 environmental objects.
Collect all orbs in the game.
Defeat Project S on Soldier or Warrior mode.
Inflict altered states on your enemies 50 times.
Defeat Sangrigor.
Defeat Brigard.
Defeat Birk on Soldier or Warrior mode.
Defeat 50 enemies using secondary weapons.
Defeat Babylon on Soldier or Warrior mode.
Defeat all Royal Scorpions.
Use 100 potions.
Defeat 1,000 enemies.
Defeat the Minotaur
Defeat Iktala on Soldier or Warrior mode.
Be revived by the Valkyries after falling in combat.