Yūma Motoki progressed from Esperion's Junior Youth team to the senior youth setup, showcasing his advancement within the club's academy. He operates as a forward and wears jersey number 29. Physically, he stands 174 cm tall, weighs 65 kg, and possesses blood type B, with his birthday on August 22. His most distinctive feature is his double teeth. Motoki exhibits a highly talkative nature during matches and daily interactions. Despite being a first-year senior youth player, his exceptional skills and physical resilience allowed him to train effectively with the A-team starters. Many peers, including other promoted talents, struggled to adapt to the intensity and pace, yet his performance positioned him as an early candidate for regular first-team selection. His background includes a long-standing childhood connection to Anri Kaidō, daughter of the president of Denki Kaidō—Esperion's primary sponsor. Their relationship remains strained, with Anri reportedly disliking him despite their shared history.