Radiant Solar, Sefris of the Hidden Ways, Fiend Hunter, and Cloister Gargoyle

Prerequisites

• Radiant Solar on the battlefield
• Sefris of the Hidden Ways on the battlefield
• Fiend Hunter in hand
• Cloister Gargoyle in hand
• available

Steps

1. Cast Fiend Hunter by paying its mana cost
2. When Fiend Hunter enters, it and Radiant Solar trigger
3. Resolve the Fiend Hunter trigger, exiling Cloister Gargoyle
4. Resolve the Radiant Solar trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Fiend Hunter
5. When Fiend Hunter dies, it triggers, returning Cloister Gargoyle from exile to the battlefield
6. When Cloister Gargoyle enters, it and Radiant Solar trigger
7. Resolve the Cloister Gargoyle 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 Fiend Hunter from your graveyard to the battlefield
10. When Fiend Hunter enters, it and Radiant Solar trigger
11. Resolve the Fiend Hunter trigger, exiling Cloister Gargoyle
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 Fiend Hunter
14. Repeat from step 5

Results

• Near-infinite ETB
• Near-infinite LTB
• Near-infinite death triggers
• Near-infinite lifeloss for all players
• Near-infinite sacrifice triggers