Kinzo's second child. Under normal circumstances, she would have lost her place in the Ushiromiya family when she married, though she managed to retain her name on the family register when she had her husband Hideyoshi adopted into the family and gave birth to Kinzo's first grandchild, George.
Eva is cheerful and mischievous, but also sinister and greedy. She is hostile towards her older brother Krauss, and rallies the other siblings against him in their fight for the family inheritance. She also looks down on Krauss's wife Natsuhi for not being related to the Ushiromiya family by blood. Because she believes George to be the rightful head of the Ushiromiya family, she is cruel towards the servant Shannon, as she suspects her of being his lover.
Despite her insidious personality, however, she treasures her husband and son more than anything, but fears that she is too domineering towards them. She is skilled in various martial arts, and said to be excellent at cooking.

In Banquet of the Golden Witch, Eva solves the riddle of Beatrice's epitaph and returns from Rokkenjima as the head of the Ushiromiya family and sole survivor of the murder incident, but is unable to overcome the grief over losing her husband and son. As depicted in the story and TIPS of Alliance of the Golden Witch, Eva lives miserably for the next twelve years as the guardian of Ange, the only other surviving member of the Ushiromiya family, resenting her for "stealing" the role of the family heir from George until she dies of acute heart failure in the year 1998.