Cast Mourning by paying 2 life if able, or otherwise.
Each creature you control's extort ability triggers.
Resolve the first extort trigger, causing you to pay 2 life if able, or W/B otherwise, causing each opponent to lose 1 life and you to gain that much life.
Repeat step 3 for each remaining extort trigger.
Resolve Mourning, attaching it to a creature you control.
Activate Mourning by paying 2 life, returning it from the battlefield to your hand.
Repeat until an opponent loses the game due to having 0 or less life.
This clever loop turns the self-bouncing Aura Mourning into a bottomless well of black mana payments, bypassing traditional resource limits with K'rrik, Son of Yawgmoth's life-substitution ability. Every time you recast the enchantment, Pontiff of Blight grants your board a cascade of extort triggers that drain your opponents while feeding right back into K'rrik's life payments and your own lifelink buffers. Meanwhile, Umori, the Collector sits quietly in the background, shaving generic mana off your continuous spell casts to keep the engine humming smoothly.