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, Kor Celebrant triggers, causing you to gain life.
Resolve Kor Skyfisher. When it enters, it and Kor Celebrant trigger.
Resolve the Kor Skyfisher trigger, returning it from the battlefield to your hand.
Resolve the Kor Celebrant trigger, causing you to gain life.
Repeat.
This loop leverages cost reducers and life-tracking to turn a single bounce creature into an unstoppable engine. With The Immortal Sun and Defiler of Faith both actively reducing the cost of white spells by a total of {2} and {W}, you can cast Kor Skyfisher for free while paying life to satisfy its mana requirements. Every time Kor Skyfisher enters the battlefield, it triggers its own self-bounce ability alongside Kor Celebrant, which cushions the life payment with continuous lifegain while Defiler of Faith pumps out an endless army of 1/1 Soldier tokens.