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