Catherine is the star knife-thrower in a circus. When Trowa Barton, pilot of the Heavyarms gundam, joined the circus, Catherine was frightened by his calm eyes, which seemed to beg for death. After Trowa brought Heero to the circus to recover from his self-detonation, Catherine took care of him, making him the soup that is always served to guests. Soon afterwards, he and Trowa left.
Several weeks passed by before Catherine and Trowa met up again; Trowa had lost his memory, and the circus took him in once more. When Duo and then Quatre appeared at the circus, Catherine nearly threatened them with bodily harm, if they even attempted to take Trowa away. Trowa eventually left anyway; regained his memories; and, after the war, rejoined the circus yet again.
Catherine is a woman of strength for her utter fearlessness in jumping into Heavyarms and punching Trowa for being a stupid fool and for speaking her mind, regardless to who it is, whether a teenaged terrorist or a threatening OZ soldier.