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