Tachibana Kimika

Kimika is Zakuro's classmate and her closest friend, though she considers that she betrayed their friendship and because of that she often treats her coldly in an attempt to alienate her. Kimika's an explosive girl who dabbles in chemical science and it's no surprise she became a 39th president of the Kita High Science Club. She also joined the Track and Field Club in order to improve her poor reflexes. Just like Zakuro, she is also the frequent target of bullying. After Zakuro's death, she'll become one of the most devoted followers of Takuji.

Edited from Wikipedia and Kickstarter page