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