Hilda Arc Edit
Katze was introduced as the representative of Regiment Hex at the Bandire. She began arguing with the Vatican representative and personal nemesis, Meiya Romano, regarding peace. When the time came to choose a side, she chose Greneda due to her hatred for Meiya. When the fighting started after the sides were chosen, Katze and Meiya fought each other until Kinichi Tohyama (Kana) put an end to it. After the "Seven Stars of the Golden Shell" was split after being removed from Aria H. Kanzaki body, Katze took one and retreated into the mist back to Germany.
Normal Life Arc Edit
Katze was briefly mentioned by Tamamo as having fought Meiya to a stalemate before retreating to her base in Berlin with the Liberty Mason exorcists searching for her.