About me: after laito pushed cordelia from the balcony, richter, found her dying. she asked him to cut out her heart and implant it into another body. he did as she asked and implanted it into yui, an abandoned girl who had the ideal body for cordelia's heart. he then handed yui to vampire hunter seiji komori, to avoid "cordelia" from being taken away by his brother, karlheinz. seiji, who was also a priest, owned a church and raised yui since then as his daughter. seiji never told yui he was not her biological father and instead, told that her mother had died when she was a child. because cordelia was the daughter of the demon king, her blood had a power flowing within it. since her heart is inside of yui, she is a power blood bank for the vampires. all the brothers note that yui's blood is of the "finest quality." in addition, her chest will hurt when "cordelia" reacts to something. this is further proven by the fact that some information about yui lists her as "human?" since she has a heart of a vampire but the body of a human. when she was 17 her father told her he was moving abroad for work and she was being sent to japan. the brothers tell her she was given up as a sacrifice.