Kaya Frebe (カヤ・フレーベ) was the late wife of Ryuuji Sogabe as well relative and later guardian of Lillie Weiss.
Kaya was a tall, blonde girl with blue eyes and long hair.
Kaya was severely afflicted by neurological problems. Due to this, she barely got out of her house, causing her problems to socialize.
Kaya is of German ethnicity, with light blonde hair and blue eyes. She is slender. She has an adventurous and amicable demeanor with a traditionally feminine style of behavior. She is friendly and approachable, traits that make her attractive to Ryuuji.
Kaya is a relative of Lilie, the player behind Cello. After the death of Lilie's parents, Kaya adopts her and acts as her legal guardian. In 2009, Kaya meets Ryuuji, the player behind Flugel, while he is in Germany. They eventually fall in love and marry. However, Kaya later dies, leaving Ryuuji to take care of Lilie.