Hailing from Okinawa, Ryunosuke Tsunashi keeps close bonds with his family through regular communication. His parents divorced; his fisherman father accrued debts while his mother remarried Okinawa's influential "Hotel King," exposing Ryunosuke to hotel environments where he learned conversational English from international guests.

Standing 190 cm with light brown hair and golden eyes, his physique earns a "Wild and Sexy" commercial label—a perception he dismisses in favor of a simple country-boy identity. This contrasts sharply with his industry ranking as Japan's second most desirable male celebrity.

As TRIGGER's stabilizer, Ryunosuke mediates between members and fosters unity via shared meals and communication, though Tenn repeatedly removes him from group chats. His disciplined routine features early jogs, cooking Okinawan dishes like goya chanpuru with hometown ingredients, and household management. He savors Okinawan awamori but turns troublesome when drunk, dancing or doodling on his stomach. Cold weather challenges him due to his subtropical roots.

Renowned for kindness, he adopts brotherly roles toward younger idols, defusing conflicts between TRIGGER’s Gaku-Tenn or IDOLiSH7’s Tamaki-Sogo. He comforted Nagi after a forgotten birthday by offering his palm for IDOLiSH7's birthdates. Comparing himself to mood-boosting Shequasar drinks, he aims to uplift others.

Beyond performing, Ryunosuke excels at fish preparation, favors comedies, and binge-watches dramas amid busy schedules. Quirks include ticklish feet, denim preference, and photographic clumsiness—exemplified when he humorously posed seriously with an eggplant during a magazine shoot, amusing TRIGGER.