Rhys, the Evermore + Reveillark + Solemnity + Yahenni, Undying Partisan

Rhys, the Evermore

Reveillark

Solemnity

Yahenni, Undying Partisan

How it works

1. Cast Rhys by paying 1
2. When Rhys enters, it triggers, giving Reveillark persist until end of turn.
3. Activate Yahenni by sacrificing Rhys.
4. Activate Yahenni by sacrificing Reveillark.
5. When Reveillark dies, its ability and its persist ability trigger.
6. Resolve the persist trigger, returning Reveillark from your graveyard to the battlefield without a -1/-1 counter on it due to Solemnity.
7. Resolve the second trigger, returning Rhys from your graveyard to the battlefield.
8. When Rhys enters, it triggers, giving Reveillark persist until end of turn.
9. Resolve the Yahenni ability from step 4.
10. Repeat from step 3.