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