Find Morkvarg and Get Rid of the Werolf – In Wolf’s Clothing – The Witcher 3 Wild Hunt
To find Morkvarg go to the back of the garden and into a hut:
After you speak with and fight Morkvarg pick up the werewolf meat in the pile near the entrance. Then go into the cave near the hut and fight Morkvarg again:
Afterwards feed him the Werewolf meat, which can be found in the quest items tab, to get rid of the werewolf in the garden.