Kenna Yatsushiro (八代 拳奈, Yatsushiro Kenna) is a senior of Class 3.
Yatsushiro is a tomboy, who is considered rougher than the guys. She finds stairs a pain, so she jumps out of windows, and once when she couldn't figure out how to open a door, she destroyed it instead. Despite this, she does have a girly side, as she developed a crush on one of her fellow classmen. She has poor handwriting, but after a week of practice with Kouki Akune, her penmanship improves to a level where she is no longer embarrassed by it.
Yatsushiro has light purple hair (black in the anime) and dark green eyes. She wears the standard girl's uniform of Hakoniwa Academy, though without the tie. Ten years later, Yatsushiro wears a kimono.
Student Council Executive Arc
Yatsushiro requests that that the Student Council write a letter for her, having seen Medaka Kurokami's impressive penmanship. Medaka assigns the job to Akune, who discovers that Yatsushiro wants him to write a love letter for her. Recognizing her feelings due to his own love for Medaka, he agrees to write a letter that will cause any man to fall for her. After being scolded by Medaka though, he instead comes back to Yatsushiro to help her improve her writing. After a week, Yatsushiro presents her crush with a love letter she has written herself. Later, while looking for a new model for Kizashi Yuubaru to paint, Akune approaches her to ask for her cooperation. She rejects him with a slap to the face.
Yatsushiro is seen being chastised along with Hisshuu Kanoya, Mahibi Moji, and members of the Kendo Club by Harigane Onigase of the Public Morals Committee for their improper clothing. Yatsushiro admits that Onigase might have a point, but points out the Student Council's flagrant disregard for the school's dress code.
Kumagawa Incident Arc
At the end of the semester, Yatsushiro is present for Medaka's speech. She is horrified by Misogi Kumagawa's new rules. On August fifteenth, Yatsushiro is among the students who come to the Vice-President's Battle to cheer for Kuudou Hinokage. Yatsushiro is among the students who boo Class -13 after the Vice-President's Battle ends.
Unknown Shiranui Arc
At the end of the academic year, Yatsushiro is among the graduating students present at the Hakoniwa Academy graduation ceremony.
Bouquet Toss To The Future Arc
Yatsushiro is among the students who confront Medaka at the beginning of the 100 Flowers Run, holding flower number eighty-nine. She and the others are all blown away by Medaka's Kurokami Final. All present wonder if Medaka thinks of their time together as good memories. Her message to Medaka is that health comes first (and to ask if her handwriting improved).
Ten years later, Yatsushiro is a calligrapher.