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