Orzhov Life Drain Combo for Commander

Athreos allows you to return creatures from your graveyard to your hand, while Necropotence enables you to draw cards while putting them into your graveyard. This synergy allows you to leverage the draw power of Necropotence to fill your graveyard with creatures and then use Athreos to return them to your hand for re-casting.

This is a classic life-drain combo. Whenever you gain life, Sanguine Bond triggers and causes your opponents to lose that much life, while Exquisite Blood triggers and gains you life whenever an opponent loses life. This creates a loop that can potentially eliminate all opponents if you can trigger either card multiple times.

Demonic Tutor allows you to search your library for any card, making it an excellent way to find Ad Nauseam. Ad Nauseam allows you to draw cards equal to the number of cards in your library, revealing them until you hit a card with a CMC you can't pay. This can set up a strong draw engine to find key pieces for your strategy.

Dark Ritual gives you a burst of mana in the early game, allowing you to cast Persecute on turn 2. Persecute can wipe out a color from your opponent's hand, especially if you can catch them off guard with the extra mana from Dark Ritual. This can severely disrupt your opponents' strategies early in the game.

Both Reanimate and Animate Dead are powerful reanimation spells that can bring back powerful creatures from your graveyard. Using these cards together allows you to consistently bring back threats after you have sacrificed or discarded them, enabling a strategy focused on using high-impact creatures to overwhelm your opponents.