Cast Kor Skyfisher by paying 0 and 2 life due to Defiler of Faith and Pearl Medallion.
Defiler of Faith triggers, creating a 1/1 Soldier creature token.
When the Soldier enters, Liliana the Faultless triggers, causing you to gain life.
Resolve Kor Skyfisher. When it enters, it and Liliana the Faultless trigger.
Resolve the Kor Skyfisher trigger, returning it from the battlefield to your hand.
Resolve the Liliana the Faultless trigger, causing you to gain life.
Repeat.
By combining Defiler of Faith with Pearl Medallion, you completely eliminate the mana cost of casting Kor Skyfisher, allowing you to repeatedly deploy it for free at the cost of your life total. Every time you cast the Skyfisher, the Defiler steps in to trigger a steady stream of 1/1 Soldier creature tokens. As those tokens enter the battlefield, Liliana the Faultless notices their arrival and rewards you with a continuous influx of life to offset the Defiler's health payment. Finally, when Kor Skyfisher itself hits the board, its mandatory bounce ability scoops it right back to your hand so the entire cycle can begin anew.