Riku is a calm, cool, collected child who is not afraid to go far beyond his limits. He is also somewhat cold but respectful. He loves his father, Shigeru Sanada but the latter always pushed him away. As a result, Riku grew to resent his father and envy his deceased half-brother, Hatori. However, he has a good and loving relationship with his paternal grandmother, Kiyomi, who mainly raised him.
Riku is a young boy with short silver hair, ice blue eyes and pale skin. He wears a high-collared, sleeveless yellow shirt with a zipper that reaches to roughly the location of his sternum. He wears black shorts and white shoes with grey soles and blue stripes on either side. Riku also has light blue wristbands on each of his hands, along with a thinner, yellow band around each blue one.
- Riku was based on the character with the same name from the Kingdom Hearts franchise.
- January 9th, Riku's birthday, was Coming of Age Day in Japan in 2012.
- Riku's name means "land" in Japanese.