Activate Woe Strider by sacrificing Tenacious Dead.
When Tenacious Dead dies, it, Totentanz, and Pitiless Plunderer trigger.
Resolve the Pitiless Plunderer trigger, creating a Treasure token.
Resolve the Totentanz trigger, creating a creature token.
In response to the remaining trigger, activate Woe Strider by sacrificing the creature token.
When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Woe Strider ability from step 5.
Activate two Treasure tokens by tapping and sacrificing them, adding .
Resolve the Tenacious Dead trigger, paying 1 to return it to the battlefield from your graveyard.
Resolve the Woe Strider ability from step 1.
Repeat.
This resilient loop relies on Woe Strider to continually sacrifice your creatures, fueling Pitiless Plunderer to generate a steady stream of Treasure tokens every time something dies. Totentanz, Swarm Piper ensures that whenever your nontoken creatures hit the graveyard, you get a fresh Rat token to feed back into Woe Strider's sacrifice outlet. Meanwhile, Tenacious Dead acts as the recurring centerpiece of the engine, using the mana from those Treasures to cheaply resurrect itself each time it falls.