This is a four-mission campaign that I've been planning for a while.  The missions aren't really very strongly connected; instead, each is based on a notable battle from Fenix's past.
 

Mission 1: Birth of a Hero-- Fenix's first battle.  A hunt for rebellious Protoss on Aiur.

Mission 2: A Historic Meeting-- The first encounter between Fenix and Tassadar.

Mission 3: First Contact-- The tumultuous first meeting between Protoss and Terran.

Mission 4: The Fall-- Fenix's death at the defense of Antioch.