Rotten Blood features a Taint mechanic similar to that of Soul War. Taints are obtained in the same way (geting one taint after killing each boss) and each one increases the experience and loot of creatures in the location (based on the team member with the fewest taints).
Taints will increase your chance of dropping a Bag You Covet from the four bosses, sons of Bakragore. They also give you the chance to get Tainted Hearts and Darklight Hearts from regular creatures in Rotten Blood.
Bakragore's taints are:
Taint #1: Monsters that attack melee have a chance to switch positions with a player within a certain radius of distance. It will be indicated 2 seconds before it happens through an effect on the SQM where the target player is currently.
Taint #2: Creatures can cause Root effect on players with at least 2 taints and also attack them with a fourth element that varies depending on the hunting location: Death (Jaded Roots), Earth (Putrefactory), Energy (Gloom Pillars), or Fire (Darklight Core).
Taint #3: If a creature dies, a creature known as Bloodjaw, can immediately appear in its place. Bloodjaws have more hitpoints and deal considerably more damage. They give experience but not loot.
Taint #4: Your character takes increased damage from all sources in Rotten Blood.
Taint #5: Once you have obtained the first 4 Taints, you will be able to face the boss Bakragore but this is just the beginning, when you defeat him, you will receive the fifth and final Taint. This will increase the challenge of hunting and killing bosses in Rotten Blood as the final Taint will increase the effect of each of the first four Taints:
Bakragore's + Taint #1: Increases the chances of a creature switching positions with you.
Bakragore's + Taint #2: Creatures can inflict Fear on you.
Bakragore's + Taint #3: Bloodjaws will spawn from dead creatures more often. The number of summons in boss fights will also increase.
Bakragore's + Taint #4: Damage taken from all sources in Rotten Blood is increased even further.
The final Taint will increase your experience and loot as an additional Taint. However, this only applies to the individual player and does not influence the level of Taints for the group.
For example, if character A has 2 taints, B has 3 plus the final taint, C has 2 taints plus the final taint, and D has 4 taints, the group's taint level is 2. Characters B and C carry the Final Taint that increases the impact of both taints on them: creatures switch places with them more often, creatures can inflict Fear effect, their loot and experience are improved as if they had an additional Taint.
The final Taint gives you a chance to get essences from the 4 bosses, each boss has its own essence type that can only be obtained specifically from the respective boss. The more Taints you have in addition to the final Taint, the higher the chances of obtaining a boss' essence.
There are a few ways to get rid of taints:
When suffering from four taints, players who successfully defeat Bakragore will have their regular taints reset.
Failing in the battle against Bakragore will erase the last two taints from the whole team and also reset the progress of two random bosses. The erased progress will be the same for the whole team.
After 68 hours of getting a taint, players are able to reset them by talking to A Bloodshade.
A player who has regular taints plus the final taint can choose to reset all of them or just the regular ones.