Cavalier of Night + Activated Sleeper + Yahenni, Undying Partisan

Cavalier of Night

Activated Sleeper

Yahenni, Undying Partisan

How it works

1. Activate Yahenni, Undying Partisan by sacrificing Cavalier of Night.
2. When Cavalier of Night dies, it triggers, returning Activated Sleeper from your graveyard to the battlefield as a copy of Cavalier of Night.
3. When Activated Sleeper enters the battlefield, its first triggered ability from Cavalier of Night triggers; choose not to sacrifice a creature.
4. Resolve the Yahenni, Undying Partisan ability from step 1.
5. Activate Yahenni, Undying Partisan by sacrificing Activated Sleeper.
6. When Activated Sleeper dies, its last ability from Cavalier of Night triggers, returning itself from your graveyard to the battlefield as a copy of Cavalier of Night.
7. When Activated Sleeper enters the battlefield, it triggers; choose not to sacrifice a creature.
8. Resolve the Yahenni, Undying Partisan ability from step 5.
9. Repeat from step 5.

This clever loop creates an endless cycle of sacrifice and resurrection using the recursive nature of the graveyard. By feeding Cavalier of Night and the copying-fresh Activated Sleeper into Yahenni, Undying Partisan's sacrifice outlet, you continuously trigger death and entry events. Because Activated Sleeper can enter as a copy of the Cavalier each time it's brought back from the graveyard, the chain feeds endlessly into itself to generate infinite sacrifice and enter-the-battlefield triggers.