The Unsheathe Ash of War is a katana move that you can equip and learn. This item grants affinities and skill to an armament. It is only usable when you have equipped a katana.
Getting to the location of the Unsheathe Ash of War is quite easy. You will need to spot a small brown ball that will be sat in the water which is surrounded by many crabs. Simply kill the ball and you shall obtain the ash of war. This guide will give you the exact location of the Unsheathe Ash of War in Elden Ring
Unsheathe Ash of War Location – Elden Ring
The location of the Unsheathe Ash of War is located east of Limgrave. From “The First Step” resting area you will need to make your way east. Pass through the waters and on the other side of the lake you will reach your desired destination.

Once you reach the area, you will notice a group of crabs slowly ascending from the waters. That is where you will find the rolling ball that is containing the Ash of War. Your objective here will be to locate the rolling brown ball and kill it.

When the ball has been killed, you will automatically get the Unsheathe Ash of War move!