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