Cast Kor Skyfisher by paying 0 and 2 life due to Defiler of Faith and The Immortal Sun.
Defiler of Faith triggers, creating a 1/1 Soldier creature token.
When the Soldier enters, Aunt May triggers, causing you to gain life.
Resolve Kor Skyfisher. When it enters, it and Aunt May trigger.
Resolve the Kor Skyfisher trigger, returning it from the battlefield to your hand.
Resolve the Aunt May trigger, causing you to gain life.
Repeat.
This clever loop relies on stacking cost reductions to cast Kor Skyfisher for free, utilizing The Immortal Sun's generic reduction alongside Defiler of Faith's life-payment option which slashes the white mana requirement entirely. Every time you cast the Skyfisher, Defiler of Faith triggers to create a 1/1 Soldier creature token, which in turn triggers Aunt May to pad your life total with each new arrival. Finally, Kor Skyfisher's own entry forces you to bounce a permanent, neatly returning itself to your hand so you can immediately repeat the entire process.