Start Location: Draven at the Eternal Throne
Note: This quest was only available via a pre-order bonus DLC called the "Death Rides Pack". So unfortunately if you were unable to grab that, you will have to miss out on this on unless you buy it as seperate DLC.
The Eternal Throne
Speak to the weapons trainer Draven in the Eternal Throne. He will give you a side-quest to track down and kill the bloodless (ghostly versions of powerful enemies). He will also give you a talisman that will allow you to see and attack them.
There are six of these enemies hidden throughout the first two worlds, with three residing in the Forgelands and the remaining three chilling out in the Kingdom of the Dead.It is possible to see them without the talisman but you will be unable to touch or interact with them in any way.
Here are their locations:
The Forge Lands
1. Stonefather's Vale - Once you have the talisman, head up to where we found the Book of the dead page in the North east corner.
2. The Fjord - On top of the large ruin on the lake that you need death grip to explore.
3. Baneswood - After travelling through baneswood and going through the circular gate to the East on the way to the Charred Pass. You will find it at the circular structure on the hill to the right.
The Kingdom of the Dead
1. The Maw - After crossing the bridge to the west, ignore the gate leading to Serpent's Peak and continue to the west. You will find this guy at the dead end just before the drop off point leading to the ruins below.
2. Lair of the Deposed King - In the large square room with the locked skull door in the Lair of the Deposed King.
3. Boneriven - You will find this Bloodless at the very end of Boneriven, an optional dungeon.
After dispatching them all, return to draven to complete the side-quest.