Here is the full list of all 55 Onimusha: Warlords achievements.
Complete the game on Normal without enhancing swords or using Jewels.
Collect all files.
Win a power struggle with a demon.
Find the beetle on the tree trunk.
Spot the flock of wild geese at dusk.
Unlock Samanosuke's alternate outfit.
Complete the game on Normal without using herbs or medicine.
Defeat Fortinbras.
Obtain the Bishamon Sword.
Collect all maps.
Defeat Marcellus's final form.
Strike Marcellus's final form with a Deflect Critical attack.
Open the gate to the Demon World.
Complete the second half of the Dark Realm.
Collect all Fluorite.
Complete the first half of the Dark Realm.
Defeat Hecuba.
Solve all number puzzles.
NEW_ACHIEVEMENUse Magic Jewels to increase Magic Power to maximum._DESC_2_7
Solve all decoder boxes.
Obtain all armor for Samanosuke.
Defeat a demon by knocking it down the waterfall.
Absorb souls from carp.
Use Power Jewels to increase Vitality to maximum.
Use the Decorated Sword to enter the East Area.
Obtain all long-range weapons.
Enhance the gauntlet to maximum.
Defeat Barabazuu.
Kill a demon with a battering ram.
Enhance all swords to maximum.
Obtain the Vision Staff.
Defeat Stylado.
Obtain the Sacred Knife.
Cut down bamboo in the bamboo forest.
Speak to the first and second old moth man.
Strike a demon with Kaede's Special Attack.
Obtain the Rosary of Communication.
Enhance all orbs to maximum.
Unseal the path to the Keep Underground.
Obtain the Arashi.
Defeat Marcellus.
Solve the crest puzzle.
Enter the abandoned keep.
Obtain the Kouen.
Defeat Osric.
Save a soldier under attack by demons.
Enhance equipment at Magic Mirror.
Obtain the Shiden.
Use a Special Attack to kill a demon.
Use the gauntlet to absorb demon souls.
Complete the game on Ultimate difficulty.
Complete the game in less than 3 hours.
Complete the game and get an S Rank.
Complete all stages of Oni Spirits.
Unlock Kaede's alternate outfit.