Mitsurugi Sachi

She is the childhood friend of the protagonist who learns that the protagonist is wielding a sword again, she begins joining him in armored combat. She is the student council president of the school.

She has a habit of taking on troubles by herself and is unable to leave people who are in trouble alone. With her bright and cheerful personality, she partakes in both the literary and military arts and does everything from event management to after-school tea parties. This is the culimation of her hard work.

She has been in love with the protagonist for a long time, but has been unable to confess her love to him due to her unlucky disposition. The protagonist has never noticed her obvious feelings.