Shin Sato is a 26-year-old idol from Nagano Prefecture who embraces the stage name "Sugar Heart," a play on her surname Sato (砂糖, sugar) and the kanji for heart (心) in her given name Shin. This identity drives her performances, consistently featuring sugar and heart motifs like tossing heart shapes to fans. While she claims a youthful appearance, observers frequently note she looks her actual age. Her theme color is cerise pink, matching her classification as a passion-type idol. Financial limitations heavily shape her idol activities. She handcrafts all her costumes, resulting in outfits that maintain cuteness and a predominantly pink aesthetic but reveal visible imperfections upon close inspection, such as accessories secured with tape. This economic reality contrasts sharply with her persistent projection of sweetness and charm. Her personality mixes exuberance with underlying anxiety. Shin frequently references her own cuteness and demands reassurance from her Producer about being "cute enough," employing "sweetie attacks" to sway executives. This stems from a fear that without her "sweetie" trait, only bitterness would remain. A history of overexertion led to multiple job dismissals before becoming an idol. She repeatedly invites her underage unitmate Nana Abe for late-night drinks, necessitating Producer reminders about Nana's minor status—a detail Shin habitually "forgets." She addresses Nana as "senpai." Relationships are central to her narrative. Beyond Nana Abe, she shares close bonds and drinking sessions with fellow Yoi Otome unit members Kaede Takagaki, Miyu Mifune, and Sanae Katagiri. She is also affiliated with Kirari Moroboshi and Shizuku Oikawa in the unit fav+rica, and maintains a noted friendship with fellow Nagano native and similar-aged Marina Sawada. Her personal preferences include meat dishes and alcoholic beverages. Her hobbies encompass dressing up and creating outfits, directly supporting her costume-making activities. Physically, she stands 166 cm tall with dirty brown hair and turquoise eyes. She has AB blood type and measurements described as "Good-Small-Good♪". She shares her July 22 birthday with Meguru Hachimiya and Genbu Kurono.