Preston, the Vanisher + Delney, Streetwise Lookout + Sefris of the Hidden Ways + Yahenni, Undying Partisan + Bloodboil Sorcerer

Preston, the Vanisher

Delney, Streetwise Lookout

Sefris of the Hidden Ways

Yahenni, Undying Partisan

Bloodboil Sorcerer

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 Bloodboil Sorcerer from your graveyard onto the battlefield.
5. When Bloodboil Sorcerer enters, it triggers once and Preston triggers twice due to Delney.
6. Holding priority, activate Yahenni by sacrificing Bloodboil Sorcerer.
7. Resolve a Preston trigger, creating a token copy of Bloodboil Sorcerer that is a 0/1 Illusion.
8. When the Bloodboil Sorcerer token enters, it triggers twice due to Delney.
9. Resolve the Bloodboil Sorcerer token triggers, venturing into Undercity twice.
10. Resolve the second Preston trigger from step 5, creating a token copy of Bloodboil Sorcerer that is a 0/1 Illusion.
11. Repeat steps 8 and 9 one additional time.
12. Resolve the Bloodboil Sorcerer trigger from step 5, venturing into Undercity and completing Undercity.
13. Repeat from step 2.

This intricate loop relies on the remarkable synergy between Delney, Streetwise Lookout and Sefris of the Hidden Ways, where Delney's static ability doubles the triggered abilities of Sefris and other low-power creatures. By looping the entry of Bloodboil Sorcerer—recursively returned from the graveyard and copied as a 0/1 Illusion thanks to Preston, the Vanisher—you repeatedly seize the initiative to barrel through the Undercity dungeon. Yahenni, Undying Partisan safely handles the sacrifice outlet requirements along the way, converting your continuous cycle of creature deaths into a massive wave of value that completely clears the dungeon over and over again.