Out of the four young pilots assigned to the Le Creuset Team of ZAFT, Yzak is the most loyal to the cause. He is portrayed as being competitive, hotheaded, and extremely impulsive. It is also seen that Yzak is highly competitive with Athrun Zala in terms of leadership. His best friend is Dearka Elsman. Yzak kept the scar to constantly remind him of the pain that the Strike has caused. On more than one occassion Yzak's temper has gotten the best of him, such as when he shot down a civilian shuttle believing it to be a unit of escaping soldiers. Throughout SEED, Yzak remains this way until the Battle of Panama, when Yzak truly sees the horrors of war. Once he forms the elite Joule Team under his aegis, he becomes more level-headed and much more of a leader. However, a meeting with Dearka (who had defected after JOSH-A), made Yzak see how twisted the ZAFT leadership was becoming, especially after witnessing the destructive power of the GENESIS causing him to question ZAFT. In Destiny, Yzak removes his scar and retains his level headed attitude, becoming more of a mentor to inexperienced pilots and presumably signaling an end to his grudge against Kira. However, he is still hot-headed and is prone to small bursts of anger as seen in his unexpected reunion with Athrun during the Junius Seven drop, though he isn't as impulsive as he was before.