Ryuugen Kamiki, born Genzou Tanuma, is a renowned shamisen performer. He is married to Sayuri Tanuma and the adoptive father of Souichi Tanuma and Mai Tanuma, who bear their biological mother's surname.

His chosen surname "Kamiki" blends the Japanese characters for deity (神) and tree (木), while "Ryuugen" incorporates flow (流) and samisen string (絃). His birth name "Genzou" signifies source (源) and structure (造), and "Tanuma" means rice paddy (田) and swamp (沼).

Ryuugen is the biological father of Setsu Sawamura, born from a past relationship with Umeko Sawamura, making him Setsu's child's biological grandfather. He abandoned Setsu and Setsu's older half-brother Wakana Sawamura during their childhood, leaving them to be raised by their grandfather Matsugoro Sawamura. This long absence established him as a Disappeared Dad figure.

As head of the influential Kamiki school of shamisen, his adoption of Souichi and Mai created visible tension between Umeko Sawamura and Sayuri Tanuma. Ryuugen directly influences his biological son Setsu's musical journey through discouragement, declaring Setsu cannot surpass his adopted brother Souichi without formal instruction. This contributes to Setsu's emotional and creative struggles. Ryuugen's legacy as a shamisen teacher extends through both his biological and adopted children, impacting central conflicts surrounding musical identity and family relationships.