To finish this you must finish all "Chasing the ... cat" quests.
Can be unlocked only after beating the game as some of those quests are unlocked only after beating the game. Also all the chase quests are available after finishing the game, so you won't miss this one. Just open map while in Cipal, and you will see side quests marks on the map.
The vendor for poppets is in the center of Cipal - the most right vendor of all 3.