Activate Ashnod's Altar by sacrificing Wretched Throng, adding CC.
When Wretched Throng dies, it and Pitiless Plunderer trigger.
Holding priority, activate Epitaph Golem by paying 2, putting Wretched Throng from your graveyard onto the bottom of your library.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Wretched Throng trigger, putting Wretched Throng from your library into your hand.
Activate the Treasure by tapping and sacrificing it, adding .
Cast Wretched Throng by paying due to Krallenhorde Howler.
Repeat.
This loop relies on a clever death-and-return cycle fueled by Ashnod's Altar, which sacrifices Wretched Throng to generate the raw mana needed to keep the engine running. As the Throng perishes, Pitiless Plunderer steps in to provide a steady stream of Treasure tokens, turning those creature deaths into flexible mana sources. To close the loop without running out of cards, Epitaph Golem tucks the fallen Throng straight back to the bottom of your library so its own death trigger can fetch it right back to your hand. Meanwhile, the transformed Duskwatch Recruiter, known as Krallenhorde Howler, discounts your creature spells just enough to ensure you can recast Wretched Throng using the exact resources you generated along the way.