Setsuna Tokage/Synopsis

U.A. Sports Festival Arc
Setsuna finishes the Obstacle Race at 39th place. It is later revealed by Neito that she was a part of the group of Class 1-B students who went along with his plan to hold back in the Obstacle Race so that they could observe Class 1-A's Quirks and tendencies. She teams up with Itsuka Kendo, Kinoko Komori, and Reiko Yanagi for the Cavalry Battle, and doesn't object once Itsuka suggests for their team to allow Team Tetsutetsu to participate in the 1 vs. 1 battles in their place.

Forest Training Camp Arc
Setsuna is seen with Yui Kodai, Kinoko, Pony Tsunotori and Reiko when Classes A and B are heading out for the school trip. On the second day of the training camp, she listens along with the rest of her class as their homeroom teacher explains that they will be training their Quirks.

U.A. Cultural Festival Arc
Setsuna participates in Class 1-B's original play, "Romeo, Juliet and the Prisoner of Azkaban: The Return of the Kings!".

Joint Training Arc
Setsuna, along with the rest of Class 1-B are pitted against Class 1-A as part of the Joint Training Exercise. She is placed in the fourth round of match-ups. As the fourth round begins, she tells her teammates that the first team to make a move will win. She leads an ambush against Katsuki and his teammates, being fully aware of Kyoka's Quirk and came up with a countermeasure by creating a lot of noise to trick them. Setsuna then uses her Self-Amputation Quirk and splits herself into many pieces to attack Katsuki and the rest of the Class 1-A team. She also orders Kojiro Bondo and Togaru Kamakiri to trap the other 1-A opponents while distracting Katsuki. They struggle to fight back because her pieces are too small to target. She then tells her team to take out Kyoka first as she is the most troublesome.

However, Katsuki manages to protect his teammates by blasting Togaru straight in the face. This prompts Setsuna to tell her team to retreat in hopes of initiating a new strategy to ambush 1-A again. Upon realizing that 1-B is underestimating his team's strength, an enraged Katsuki commands his team to charge forward. Setsuna observes Katsuki's newfound demeanor, wondering how he managed to cooperate well with his teammates despite most likely working alone. She then attempts to ambush Katsuki once again with a combined attack with Kojiro. However, this fails as the explosive hero easily takes out Kojiro with ease. Setsuna tries to retrieve some of her dismembered parts, only to find a grenade attached to one of the parts. This creates a loud explosion from a not-so-far distance. Setsuna manages to evade the attack and believes she successfully escaped 1-A's grasp. Unfortunately, Katsuki blasts his way towards Setsuna and emits a Point-Blank Stun Grenade straight at her body. Setsuna exclaims that Katsuki changed too much as she gets engulfed in the attack.

Afterward, Setsuna and her classmates lose the match due to their plan lacking the flexibility of Juzo Honenuki, as mentioned by Vlad King. A sullen Setsuna apologizes to her team for failing to impress their class. She also apologizes to Neito for ruining their class' chance of beating Class 1-A, in which Neito tells her its alright and those who make mistakes who always grow stronger from the outcome.