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