The PK (Player Kill) system only applies on Channel 1 [CH1]. To participate, you must be at least Level 20. PvP combat, or PKing, is allowed anywhere in Madrigal except for towns, which are safe zones.

On each continent, there is a Priest of Confession who assists players in redeeming their PK count by summoning an angel. Buy an angel from [Iblis] NPC in Flaris. Once the Angel appears, you must defeat several monsters and sacrifice about 50% of your current experience to prove your worth. The amount of experience required varies depending on the type of angel summoned.

White Angel: Requires 10% of 1 level's worth of experience. Green Angel: Requires 30% of 1 level's worth of experience. Blue Angel: Requires 60% of 1 level's worth of experience. Red Angel: Requires 1 level's worth of experience. After providing the necessary experience points, you can return the Angel to the Priest, and it will disappear.