Rika Yamauchi is the main protagonist of Yōsei Yume and the leader of the group Yōsei Yume. She is a Kū Yōsei Megami of Yōsei Uchu and the rightful ruler of her home Kū Uchu. Her attacks are based on the element of light, has the ability to restore life to almost any living creature and can heal major wounds.
As a Kū Yōsei Megami, Rika is described to be beautiful. She has long silver hair that reached past her lower back with parts of her hair braided and silver eyes. Her outfit consisted of an Ancient Greek short crop top with an opal in the middle of the top, long white skirt that touched down to her feet with golden string hanging from the hems and white golden heels.
As a human, Rika has light sandy brown hair that is tied in a ponytail by a pastel pink ribbon and brown eyes. Majority of her outfits are usually pastel colors of casual and elegant style due to her status. Her main outfit she would wear is a pastel pink dress with a white cardigan and white dress shoes. As a Megami, instead of baring fairy wings like her race, she bares white angel wings.
As a Yōsei, Rika wears a flowing short white dress that barely touches her knees and wears sandals that are gold and white. She also bares white translucent fairy wings.
As a Kū Yōsei Megami, she was known as a strong and caring leader who would help those in need whether in her own world or in the other worlds in the Yōsei Uchu.
However, when Rika became a human, she started off as an insecure girl in the beginning of the series because of her trying to understand the human world after being exiled by Agor and awakening her powers again. As a human, Rika was usually quiet but is known to be curious about many things that she never experience in her homeworld. With Rika coming to terms in her human form, she began to adapt slowly but surely making new friends. During her time as a human, she still maintained her strong leadership and caring personality when leading her friends in certain situations.
In a stressful situation, Rika is known to suffer from anxiety due to the intense pressure of being the leader of the group but is reassured by her friends of how much they need her to defeat their enemies.