Currently no details of Natsume Masako life prior to becoming Cuckoo 's host body are known.
In 1889, When Masaaki was appointed to be the diplomat to France, the couple moved to Paris. Their Parisian residence had a private Japanese garden, where Masako was attacked and killed by the vampire Marietta Borgezia. In shock, she transferred her consciousness to Borgezia, expelling her life force. As Cuckoo tried to reoriented herself in Borgezia's body, Prince Masaaki entered the garden to find his wife dead and attacked seeing Cuckoo in Borgezia body, forcing her to flee.