Sōda has black wavy hair reaching just past her shoulders.
She wears a black sleeveless top and a long black skirt. She wears a black belt around her waist with a silver ring in the middle. She wears a necklace. Sōda carries around a scarf with a flower design pattern which she wears around her arms. In The Live #1 and The Live #2 stage plays the color of the scarf is grey, whereas in the Blue Glitter stage play, it is red. She wears black boots with heels.
Sōda-sensei has garnered a reputation among her students for being notoriously brisk and stern. She believes in self-sufficiency, telling a young Karen Aijo that if one desires something badly enough, they will obtain it by any means necessary.
Sōda belonged to Seisho Music Academy's 74th Graduating Class, where she served as the representative of the Actor Training Department and was considered the Top Star, lauded for being a solitary prodigy.
During her third year at school, she became aware of Ichika Saegusa's circumstance as the primary caretaker of her much younger sister, which had made it difficult for her to put in the effort their program required. It was not until the freshman Kyōko Yakumo threatened the 74th Graduating class to take the lead of "Starlight" in their last Seisho Festival that Sōda decided to befriend Ichika, as she believed her heart gave her the upper hand as an actress. They aimed to train together in order for Ichika to play the Claire to Sōda's Flora.
However, Ichika did not show up to the final audition, and Sōda eventually found out that she had missed school to take her sister to the hospital. Making her way to Ichika's home, she was surprised to find that Yakumo had gotten there before her. From a distance, she witnessed Yakumo rebuke Ichika for not showing up, but eventually tell her that she loved and admired her.
Yakumo would go on to be cast as the Claire to Sōda's Flora, but, feeling insufficient next to her, she withdrew from both the play and Seisho and wound up going to Seiran General Art Institute instead. Sōda would regretfully end up being known as somebody who had intimidated both of her partners into quitting.
After graduation, she began a career as a prolific actress, performing in the renowned stage production of "Starlight". Hikari Kagura and Karen Aijo were dazzled by her performance as Claire, and her additional words to Karen after the play was over partly inspired her to attend Seisho in pursuit of a theater career. In time, she would become the headmistress of Seisho Music Academy, with aims of teaching her students that nothing fruitful came from being in solitude like she was in her past.
Sōda was two years Yakumo's senior at Seisho. Through their interactions, Sōda came to realize that Yakumo was very much the same lonely person she herself had been before befriending Ichika, and that while her skills were up to par with her own, she lacked the heart to be a brilliant actress.
While in -The LIVE- #2 Transition Yakumo appears to treat Sōda with contempt, by the end of the play Sōda is able to reach out to Yakumo in a way she had not been able to in the past, as -The LIVE Seiran- BLUE GLITTER reveals that Sōda felt regretful about not having been able to stop Yakumo from running away from Seisho and her role as Claire in "Starlight." The manga adaptation of the play further suggests that she always believed it was Ichika that Yakumo looked up to, rather than herself.
Ichika was the bottom student of the 74th Graduating Class, whom Sōda looked down on. Upon finding out about Ichika's circumstance as the primary caretaker of her much younger sister, and learning how that had isolated her from the rest of the class, she feels sympathetic towards her, and starts feeling a need to speak up in her defense against the words of her classmates who don't know her as well.
Believing Ichika possesses the heart to make her shine as an actress, Sōda proposes to train her and help take care of her sister so that they will be able to become the leads of "Starlight" in the Seisho Festival of their last year. While that dream is cut short for matters outside of their control, it is Ichika's conviction to protect those she cares for, including Yakumo and herself, that gives Sōda her courage later in life, leading her to eventually become a headmistress at Seisho in order to teach a younger generation what she learned from her.
Sōda-sensei is honored that the Giraffe has come to Seisho to hold audition battles. As seen in both stage plays, she is willing to sacrifice the well-being of her students to entertain the Giraffe while directing audition battles. When she fails to enforce the audition battle system onto her students, she apologizes to him profusely and pleads for him not to leave Seisho, vowing to rectify her mistakes next time.
- The name Sawa means "thread, silk" (紗) (sa) and "feather" (羽) (ha/wa).
- Sawa's surname Sōda means "running" (走) (sou) and "quiver" (駝) (da).