The Master's Salve

The Master's Salve
The Master's Salve is a quest in Mark of the Assassin DLC.

You receive the quest from a Plot Point above a man in the area where you first meet the Duke. Speaking with the man and having him tell you about the salve updates your codex and starts the quest.

Listed are the three ingredients: Andraste's Mantle, drakevein, and winterberry.

Andraste's Mantle is located in a small clearing soon after you enter the East Hunting Grounds, and is probably the easiest to spot.

Drakevein is located in the East Hunting Grounds directly across a clearing from the entrance into the West Hunting Grounds behind a tree or two. Look for a small peninsula of land near a small inaccessible circle on your map.

Winterberry is found (probably last) almost immediately after you enter the West Hunting Grounds. Right next to the water where there is a viewpoint and a chest with misc. potions.

Finding all three is all you need for this quest. Upon finding the last one, the quest will be completed. Using the salve, however is utilized in a quest the player has probably already started. See The Lost Hounds.

The salve seemingly has no use for the player, but is used on the dog from The Lost Hounds for a very good reward.