Balmung Cycle Part I: The Messenger and the Heretic

In each and every hostile area exist monsters. As a law of RPGs and general fantasy: Monsters hurt things. Too often is there little reward for turning the tables on those baddies, so Balmung Cycle incorporates a degree of divine favor outside battle to reward the dedicated.

Divine favor trigger condition/reward:
Kill everything in sight without leaving the area. Each region that you successfully eradicate all monsters will earn you one of many artifacts known as Odin's Triumph. Additionally, a rare sealed chest that is usually somewhat hidden in the region will be able to be opened through some miracle. Now that's good old-fashioned genocide with a purpose!

(Supposedly there is a rare item that allows the party to see how many monsters remain in an area, but its existence has never been confirmed...)