Cast Kor Skyfisher by paying 0 and 2 life due to Defiler of Faith and Oketra's Monument.
Defiler of Faith and Oketra's Monument trigger.
Resolve the Defiler of Faith trigger, creating a 1/1 Soldier creature token.
When the Soldier enters, Aunt May triggers, causing you to gain life.
Resolve the Oketra's Monument trigger, creating a 1/1 Warrior creature token.
When the Warrior 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 turns Kor Skyfisher into a self-sustaining engine by completely eliminating its mana cost through the combined cost reductions of Defiler of Faith and Oketra's Monument. Every time you recast the Kor Skyfisher for free, both artifacts and creature generators spring into action: Defiler of Faith and Oketra's Monument reward you with an army of Soldier and Warrior tokens, while Aunt May cheerfully pads your life total with every single entry. Finally, Kor Skyfisher's own mandatory entry trigger bounces itself right back to your hand, resetting the stage so you can repeat the entire process indefinitely.