I hear the Amani trolls eat their enemies' hearts to steal their strength. They might just be on to something, <name>. With the proper treatment, the hearts of the unliving can produce potent elixirs. Hunt down the zombies that roam the Dead Scar and bring me their hearts. I'll show you the kind of enhancement we can perform to your physical prowess against the undead.
Take this draught, <name>. After you drink it, your physical strength against the Scourge will receive a boost. If you need more than this sample bring me more hearts.
The items drop from Risen Hungerers and Risen Stalkers in the Dead Scar. They are not soulbound and are not quest items (you can collect them when you don't have the quest).
After completion of this quest, you can take the repeatable quest  , which does not grant XP.