Preston, the Vanisher + Delney, Streetwise Lookout + Sefris of the Hidden Ways + Ashnod's Altar + Underdark Explorer

Preston, the Vanisher

Delney, Streetwise Lookout

Sefris of the Hidden Ways

Ashnod's Altar

Underdark Explorer

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

This magnificent loop hinges on the exquisite synergy between Delney, Streetwise Lookout and Sefris of the Hidden Ways, turning a single dungeon completion into an endless cycle of resurrection. When Sefris brings back Underdark Explorer, Delney's passive ability ensures that both the initiative trigger and Preston, the Vanisher's copy triggers happen twice over. By cycling Underdark Explorer through Ashnod's Altar for mana while Preston constantly spits out 0/1 Illusion token copies of it, you repeatedly race through the Undercity dungeon. This endless repetition allows you to trigger Sefris's dungeon completion ability over and over, letting you leverage every single resource in your library and graveyard infinitely.