Yes, it's an activated ability that costs to use. So, when you have priority, you can activate [card]Nomads En-Kor[/card], targetting [card]Daru Spiritualist[/card] (for example) 15,000 times. Then you use a "sac to gain life" ability of something like [card]Starlit Sanctum[/card] or [card]Diamond Valley[/card] to gain 15,000 (or some equally arbitrarily large) life. From there you can deck your opponent or use a win condition, like [card]Test of Endurance[/card] to win the game. It's a redundant and highly elegant little combo that just slaughters aggro decks.

Read the Flores article linked above for a more detailed explanation.

Rector kill: Oath up Academy Rector while hopefully putting Cabal Therapy in the graveyard. Flashback Therapy, sac Rector and fish out Bargain (Or something similar). Draw 17-19 cards and then Tendrils the opponent out. Reclamation up Yawg's Will in the off-chance you are unable to fetch anything with Rector after 2-3 Oath activations.

Consists of 4 Cabal Therapy, 1 Krosan Reclamation, Necropotence, 1 Future Sight, Yawgmoth's Bargain, Yawgmoth's Will, 1-2 Academy Rector and 1-2 Tendrils of Agony.

Advantages
-Many 'mini' combos get added to the deck through so many broken cards
-Rector is a good back-up engine with Oath
-The ability to win immidately after assembling the combo

Disadvantages
-Life matters
-Loss of a HUGE amount of maindeck space
-Opens you up to grave hate

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The necro issue willl be discussed in the next article.