Preston, the Vanisher + Delney, Streetwise Lookout + Sefris of the Hidden Ways + Viscera Seer + Feywild Caretaker

Preston, the Vanisher

Delney, Streetwise Lookout

Sefris of the Hidden Ways

Viscera Seer

Feywild Caretaker

How it works

1. Complete a dungeon.
2. Sefris' second ability triggers twice due to Delney.
3. Resolve the first trigger, returning up to one other creature from your graveyard to the battlefield.
4. Resolve the second trigger, returning Feywild Caretaker from your graveyard onto the battlefield.
5. When Feywild Caretaker enters, it triggers once and Preston triggers twice due to Delney.
6. Holding priority, activate Viscera Seer by sacrificing Feywild Caretaker.
7. Resolve a Preston trigger, creating a token copy of Feywild Caretaker that is a 0/1 Illusion.
8. When the Feywild Caretaker token enters, it triggers twice due to Delney.
9. Resolve the Feywild Caretaker token triggers, venturing into Undercity twice.
10. Resolve the second Preston trigger from step 5, creating a token copy of Feywild Caretaker that is a 0/1 Illusion.
11. Repeat steps 8 and 9 one additional time.
12. Resolve the Feywild Caretaker trigger from step 5, venturing into Undercity and completing Undercity.
13. Repeat from step 2.

This elegant engine transforms Sefris of the Hidden Ways into an endless dungeon-delving loop by leveraging Delney, Streetwise Lookout to double every creature-based triggered ability. When Sefris returns Feywild Caretaker to the battlefield, Preston, the Vanisher swoops in to manufacture 0/1 Illusion copies of it, while Viscera Seer is on hand to neatly tidy away the original when needed. Because Feywild Caretaker takes and advances the initiative upon entering, those doubled triggers swiftly rocket you through the Undercity dungeon over and over again, eventually unlocking every room and achieving an overwhelming victory.