Ancient Power (Dawnguard)

Background
Feran Sadri sends the Dragonborn to retrieve the petrified remains of an elder vampire from a radiant location. This quest can be repeated up to five times. Body parts include:
 * Head
 * Ribcage
 * Arm
 * Hands
 * Leg

Walkthrough
Head to the radiant location marked in the journal, the bodypart will typically be located inside a chest.

Possible locations

 * Altar of Thrond
 * Ansilvund
 * Bloodlet Throne
 * Bloodskal Barrow
 * Broken Oar Grotto
 * Bruca's Leap Redoubt
 * Chillwind Depths
 * Damphall Mine
 * Darkwater Pass
 * Dead Crone Rock
 * Dead Men's Respite
 * Druadach Redoubt
 * Duskglow Crevice
 * Falkreath Watchtower (Quest log says Crossroads Watchtower)
 * Folgunthur
 * Forsaken Cave
 * Fort Fellhammer
 * Gallows Rock
 * Geirmund's Hall
 * Gloomreach
 * Hag's End
 * Halldir's Cairn
 * Halted Stream Camp
 * Harmugstahl
 * Hob's Fall Cave
 * Hrodulf's House
 * Lost Echo Cave
 * Lost Knife Hideout
 * Moldering Ruins
 * Moesring Pass
 * Movarth's Lair
 * Orotheim
 * Orphan Rock
 * Ravenscar Hollow
 * Rift Watchtower
 * Serpent's Bluff Ruins
 * Shimmermist Cave
 * Shriekwind Bastion
 * Sightless Pit
 * Silverdrift Lair
 * Snapleg Cave
 * Stillborn Cave
 * Stony Creek Cave
 * Sunderstone Gorge (Quest log says Greywater Gorge)
 * Treva's Watch
 * Uttering Hills Cave (Quest log says Uttering Hills Camp)
 * Valtheim Towers (Quest log says Valtheim Keep)
 * Volunruud
 * Witchmist Grove
 * Yngol Barrow

Reward
After infusing the remains' lingering magical essence into the Bloodstone Chalice, the Blood of the Ancients ability granted to the Dragonborn will last for a longer duration of time:

If the ability was already listed under active effects, it will be removed upon completion of the quest as it becomes obsolete. The upgraded version of the ability can then be obtained from the chalice.

The Dragonborn will also be given  3 x Potion of Blood.

Bugs

 * You may be able to complete this quest more than five times.
 * You may be sent to collect the same petrified remains multiple times.