Out of the five young pilots assigned to ZAFT's Le Creuset Team , Yzak is the most loyal to the cause. He is portrayed as being competitive, hotheaded, and extremely impulsive. Yzak is highly competitive with Athrun Zala in terms of skill and leadership though this rivalry was mostly one-sided. Like Dearka Elsman, he also held a firm superiority complex over Naturals, deeming them inferior in all aspects when compared to Coordinators. In spite of these conflicts with Athrun, he still cares deeply for his fellow teammates, showing deep anger and sorrow over Nicol's death, being the one most affected by it, and attempting to defy orders in favor of searching for Athrun and Dearka when they went missing.

Although Yzak is known for being over-zealous and impulsive, he prefers to fight fairly; during the Battle of Panama he expresses his great distaste for "shooting at targets that can't shoot back", which causes him to doubt the ZAFT command structure after truly seeing the horrors of war. Yzak kept his scar to constantly remind him of the pain that the Strike has caused.