Activate Ashnod's Altar by sacrificing Eternal Witness, adding CC.
When Eternal Witness dies, Pitiless Plunderer triggers, creating a Treasure artifact token.
Activate the Treasure by tapping and sacrificing it, adding .
Activate Doomed Necromancer by paying , tapping it and sacrificing it.
When Doomed Necromancer dies, Pitiless Plunderer triggers, creating a Treasure artifact token.
Resolve the Doomed Necromancer ability, returning Eternal Witness from your graveyard to the battlefield.
When Eternal Witness enters the battlefield, it triggers, returning Doomed Necromancer from your graveyard to your hand.
Activate a Treasure by tapping and sacrificing it, adding .
Cast Doomed Necromancer by paying 2.
Repeat.
This clever necromantic loop relies on an engine of constant sacrifice and rebirth to churn through your graveyard. Ashnod's Altar provides the raw colorless mana while cleanly sending your creatures to the graveyard, a death that Pitiless Plunderer eagerly rewards by generating a steady stream of Treasure tokens. These Treasures supply the black mana needed to fuel Doomed Necromancer, who pulls Eternal Witness back from the dead; in turn, the returning Eternal Witness scoops Doomed Necromancer right back out of your graveyard to hand so the cycle can begin anew. Meanwhile, Temur Ascendancy grants your looping creatures haste and even lets you draw an entire deck's worth of cards if any of your revived threats happen to boast a power of 4 or greater.