Unknown Hero Soul

Unknown Hero Soul
Usage	Grants 400 souls when used.
Weight	0.0

Unknown Hero Soul (or Unknown Hero's Soul) is a Soul in Demon's Souls and Demon's Souls Remake. Souls are consumable items categorized as remnants of fallen warriors, consuming souls collects a certain number of souls that is added to the player's stock. Souls are required for players to become stronger in the game by raising their soul level as well as buying and upgrading their equipment.

The echoes of a soul found on the corpse of an unknown hero. Consume to gain souls.
Go on, if left alone, it would only serve as feed for demons...

All Unknown Hero Soul Locations Guide

Gates of Boletaria

On a small balcony, in the tower where you fight three Hoplites

The Lord's Path

On the top of the tower before the fight with the Tower Knight.

Inner Ward

After fighting the first Imperial Spy, take the tunnel and turn left. Behind some breakable crates, you can loot one from a corpse.
On the balcony you are being attacked by three ranged Boletaria Soldiers. Loot the body on the left side to obtain one.
After passing the big locked iron gate, you will be faced by many Boletaria Soldiers, on your right behind the two crossbow-wielding ones, there's an upper platform that contains x1 Unknown Hero Soul.

Smithing Grounds

Before the lever that let the water flow on the lava, there's one under the nearby stairs.

The Tunnel City

From the archstone. go right along the tunnel. Once you reach the end, turn right, go through the narrow passage. You will have to start dropping from scaffolding to scaffolding. On the third one, turn to your right and drop on the narrow wooden beam, at your right there is a corpse hanging from it. Keep dropping until you reach a platform that has a rusty iron ladder. Go down through it and you can loot Unknown Hero Soul from the body.
If you take the left path from the archstone, after the elevator room, keep going straight. Once you reach the open cavern, you can obtain one on a body, near it a Rock Worm will emerge. Video Location: Shown in our walkthrough video N7 at 2:50. Click here to watch it
In the same area, while dropping from platform to platform, you can find it next to the one that has a Chunk of Greystone.
It can be looted off a body that's inside the tight tunnel where the pool of lava is.
Video Location: Shown in our walkthrough video N7 at 37:20. Click here to watch it

Prison of Hope

Once you access the second floor, you can find one on the first cell on your left.
Video Location: Shown in our walkthrough video at 9:05. Click here to watch it
Once you access the second floor, on the room where there are two iron maidens, you can obtain one Unknown Hero Soul from the one on the right.
Located in a cell on the fourth floor. You have to use Prison of Hope 4F Cell Key to open it.
In the cell where there are multiple Iron Maidens, you can loot x1 Unknown Hero Soul from two of them.
In one of the cells on the first floor.

Island's Edge

Go around the corner to the left before the second fog door, a body against a wall has one.
After the area where you find the Adjudicator's Shield. Beyond the Silver Skeletons, turn left twice and you will find it on a body near a trap switch.

Swamp of Sorrow