Ushiromiya, Kyrie

Rudolf's second wife. She is also one of Rudolf's business partners, always assisting him in shady dealings and keeping him in line when he gets out of hand. Kyrie and Battler have bonded more as close friends with a sibling-like relationship rather than mother and son, with Battler going as far as always calling her "Kyrie-san." She is known for her "flip the chessboard" mentality, influencing Battler in this regard. She had actually dated Rudolf long before his first wife Asumu, who she envies for marrying Rudolf while she was still going out with him. They were pregnant at the same time, though Kyrie's son was believed to have been a stillborn when Asumu gave birth to her son Battler.

[Spoiler] With Rudolf as an accomplice, she is the true culprit of the Rokkenjima murders. When the gold had been discovered by the siblings after solving the epitath, Natsuhi had been accidentaly killed by Eva. The same happened to Krauss with Hideyoshi.

The tension created by Rosa's plan to send Eva in jail and keep the gold made her decide kill everyone on the island and keep the 1 billion yen cash card for her and Rudolf.

While Eva and Beatrice are "dead" in the golden room, Rudolf and her kill George, Kumasawa, Genji, Gohda, Maria and Jessica, making Battler, Eva and Beatrice, Rudolf and herself the only people alive on Rokkenjima.

She is finally killed by Eva who had just killed Rudolf and is still seeking revenge for Hideyoshi and George.

Before Kyrie dies, she tells Eva that now that Rudolf is dead, the link between them do not exist anymore and that she doesn't care of Ange. She's rather happy that it happened, saying that Rudolf was incompetent. She hopes to find a new love and begin a new life with her money. She also confirms that she is the one who killed Maria herself, and, in an alternate universe, she is the one who kills Lion.

It is later revealed that she is Battler's true mother. [/Spoiler]