Discouraged by her perceived lack of progress despite years of judo since primary school, Michi Sonoda resolved to quit after an embarrassing final middle school tournament defeat by Towa Hiura. A photo of her loss circulated online, cementing her desire for a "normal" high school life focused on academics and finding a boyfriend.

Discovering Towa enrolled at her high school, Aoba Nishi High, reignited Michi's latent passion for judo. Alongside childhood friend Sanae Takigawa and Towa herself, Michi revived the school's dormant judo club to save it from disbandment. Her initial ambivalence transformed into renewed dedication, fueled by the team's camaraderie and shared goal.

Michi exhibits a boisterous, energetic personality, often motivating teammates with playful physicality like smacking their buttocks during matches. She demonstrates leadership by encouraging teammates facing struggles, such as supporting Sanae against parental disapproval of club participation. Her hypermobility grants tactical flexibility, allowing escapes from holds like armbars.

Competing, Michi valued scoring ippons but shifted focus toward team cohesion and mutual growth. She formed strong rivalries with competitors like Ami Shiraishi and Hana Odagiri, often evolving these into respectful friendships. Her match against Shiraishi highlighted her determination and sportsmanship.

After high school, Michi pursued judo professionally, contrasting with Sanae and Anna Nagumo – a childhood friend who later joined the judo club from kendo – who did not continue in the sport. Her journey reflected a sustained commitment to judo beyond adolescence.