Kinji Tohyama[]
Kinji was Katze enemy towards the end of the Far Eastern Warfare (FEW) when she hijacked an oil tanker in an attempt to destroy Hong Kong as well as trying to kill him by shooting him in the head, which both failed. However, she was confused when he saved her after she fell from the top of a zeppelin, but was very grateful to him in her own way when he kept her and Edgar from freezing to death on Mont Blanc as well as saving her from an ice crevasse. As thanks she spoke in his defense when Director Estelle was going to execute him and was trying to save him from being turned into a witch by making him her familiar.
Meiya Romano[]
Meiya is Katze archnemesis, whom she has had battles with in the past as well as an intense hatred for her and the Vatican. She despises Meiya's religious values and beliefs to the point of wanting to fight her at every given chance. In addition, Katze mentions how she hates Meiya large breasts.
Lisa Ave du Ank[]
Hilda Tepes[]
Katze and Hilda have a mutual relationship based on their limited interaction with both having an intense hatred for the Vatican and loves the chance to battle them. However, after Hilda was defeated during the Far Eastern Warfare by and helped Team Baskerville defeat Ranpan, she considered her a traitor.