The Sacrifice Quest is something you can complete every 12 hours to earn herbs.
This Quest can be accepted at the NPC Yang-Shin.
He will send you out there to kill monsters in your level area to earn their Animal hearts.
He will reward you with herbs, but he gives you the choice of which ones you want to get.
You can bargain with him to get more herbs, but be carefull he might call you greedy and won't give you anything!
This quest has a "Level System", the higher your level the more herbs you will earn daily! If you want to know your current level at this quest, you can talk to Yang-Shin!