Rezin participated in the Battle of Fifth Luna. She damaged Kayra Su's mecha the Ra Cailum and immobilized it. However, she was unable to kill the pilot Amuro Ray arrived to provide backup. She attempted to fight Amuro but after being ordered to fall back, Rezin reluctantly retreated.
Rezin later attempted a strafing run on a Federation battleship solo. While performing this, Rezin was shot down and killed by Chan Agni via turret.
Rezin displays a sadistic love of war and violence, having joined up with Neo Zeon for no apparent reason other than to kill people. She also behaves rude towards the other Neo Zeon members, insulting Gyunei Guss and throwing a wrench at him and Quess Paraya when they make fun of her.
- Rezin's psychopathy and sadistic enjoyment of violence make her similar to Yazan Gable from the previous Gundam series Mobile Suit Zeta Gundam.