One idea...
Just put "妖刀", Youtou, like a prefix.
妖刀 村正
妖刀 虎徹
Both are thought to be evil swords in the J history. The words 村正 or 虎徹 don't have any evil meanings at all, but 妖刀 creates some mysterious connotations in the swords.
I don't know if 妖刀 Kitty chan has that kind of meaning, though.