Extort is a keyword introduced in Gatecrash, wherein it is the Orzhov Syndicate guild mechanic.  It allows players to pay additional or for spells they cast and create a small life-draining effect.
From the Comprehensive Rules:
- 702.100. Extort
- 702.100a Extort is a triggered ability. "Extort" means "Whenever you cast a spell, you may pay . If you do, each opponent loses 1 life and you gain life equal to the total life lost this way."
- 702.100b If a permanent has multiple instances of extort, each triggers separately.
- You may pay a maximum of one time for each extort triggered ability. You decide whether to pay when the ability resolves.
- The amount of life you gain is based on the total amount of life lost, not necessarily the number of opponents you have. For example, if your opponent's life total can't change (perhaps because that player controls Platinum Emperion), you won't gain any life.
- The extort ability doesn't target any player.
- Treasury Thrull -
Creature — Thrull
Extort (Whenever you cast a spell, you may pay . If you do, each opponent loses 1 life and you gain that much life.)
Whenever Treasury Thrull attacks, you may return target artifact, creature, or enchantment card from your graveyard to your hand.
 Color percentages
There is a total of 13 cards that involve extort, which divide by color as such:
- Black = 38 %
- White = 31 %
- Multicolor = 31 %