The Requiem Sword is a powerful weapon that Soki carries on his back, it has the ability to purify any enemy he strikes making it very powerful. However, this particular blade was only physically wielded as a dual weapon when he was in his true (combined Oni, Genma lord) Onimusha form. Other then that Soki can use this sword in combat in his normal form by levitating it in the air around him but must then let it rest for awhile until it glows red and then he’s able to use it again. The sword is used best when you use oni awakening thus letting you use the sword as many times as you desire creating more purple souls for every enemy you hit to keep your onimusha bar filled up.