Radiant Solar + Sefris of the Hidden Ways + Phantom Steed + White Plume Adventurer

Radiant Solar

Sefris of the Hidden Ways

Phantom Steed

White Plume Adventurer

How it works

1. Cast Phantom Steed by paying its mana cost.
2. When Phantom Steed enters, it and Radiant Solar trigger.
3. Resolve the Phantom Steed trigger, exiling White Plume Adventurer until Phantom Steed leaves the battlefield.
4. Resolve the Radiant Solar trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Phantom Steed.
5. Phantom Steed leaves the battlefield, causing White Plume Adventurer to be returned to the battlefield from exile.
6. When White Plume Adventurer enters, it and Radiant Solar trigger.
7. Resolve the White Plume Adventurer trigger, venturing into the Cradle of the Death God room, creating a 4/4 legendary The Atropal creature token and completing Tomb of Annihilation.
8. If you control two or more The Atropal tokens, put all but one into your graveyard due to the legend rule.
9. Sefris' second ability triggers, returning Phantom Steed from your graveyard to the battlefield.
10. When Phantom Steed enters, it and Radiant Solar trigger.
11. Resolve the Phantom Steed trigger, exiling White Plume Adventurer until Phantom Steed leaves the battlefield.
12. Resolve the Radiant Solar trigger from step 10, venturing into Tomb of Annihilation and into the Trapped Entry room, causing each player to lose 1 life.
13. Resolve the Radiant Solar trigger from step 6, venturing into the Oubliette room, causing you to discard a card and then sacrifice Phantom Steed.
14. Repeat from step 5.

This intricate loop utilizes Sefris of the Hidden Ways as the engine's heartbeat, triggering her ability to venture whenever creature cards hit your graveyard. By casting Phantom Steed to temporarily exile White Plume Adventurer, you set up a rhythmic dance where Radiant Solar constantly pushes you deeper into the dungeons. When the Tomb of Annihilation is finally completed, the legend rule forces extra copies of The Atropal tokens into your graveyard, which in turn fuels Sefris of the Hidden Ways to bring back Phantom Steed and repeat the whole process endlessly.