Masataka Takayanagi is a second-year student at Todo Academy and the younger brother of Mitsuomi Takayanagi, the president of the school's Executive Council. Born on November 23, he is sixteen years old and a member of the Juken Club, which he deliberately joined to oppose his brother, as the two have a strained relationship. Despite appearing as an ordinary, easygoing, and somewhat shy high school student, he is a highly skilled martial artist whose power becomes far more dangerous when he is serious or angered. He possesses a perverted inner nature that he himself dislikes, and he falls in love with Aya Natsume at first sight, though she later develops feelings for Souichiro Nagi. Masataka maintains a long-standing crush on Aya while remaining unaware that several other girls have feelings for him. Aya once described him as the calm surface that gently envelops the rapids, capturing his dual nature.

Masataka's motivations are rooted in his desire to stand apart from his elder brother and to protect his friends within the Juken Club. Over time, his ambition grows; he eventually declares his intention to become the strongest and directly challenges Souichiro. His role in the story begins as a formidable early opponent, as he easily defeats Souichiro in their first encounter, but he later loses control when tricked into a berserker rage. For a period, he serves as a training partner and guide for Bob Makihara. When Bob struggles against the sword expert Madoka Mawari, Masataka steps in and reveals himself as an anti-weapons specialist, skillfully countering her blade. He also storms his family estate to halt a battle between his brother and Bunshichi Tawara, only to arrive too late. This leads to a bitter confrontation with Mitsuomi, during which Masataka lands a devastating elbow strike that impresses his brother. In the final arc, Masataka fights Souichiro and, though he suffers a permanent scar across his face and loses his right hand and forearm to Souichiro's aura, he does not give up. He lands a ki-filled blow that, combined with the efforts of Aya and Maya Natsume, helps neutralize the antagonist Sohaku. After this, Masataka becomes the new president of the Executive Council and replaces his lost limb with a mechanical arm.

Key relationships define his character arc. His rivalry with Mitsuomi is both personal and ideological, as he joins the opposing Juken Club to rebel. His unreciprocated affection for Aya drives much of his emotional conflict. He respects Maya Natsume as a teacher and grows close to Bob as a friend and fellow fighter. Madoka Mawari later falls in love with him after he defeats and frees her from Sohaku's control, but Masataka remains oblivious to her feelings.

Masataka's development sees him evolve from an overlooked supporting fighter into a determined leader willing to endure severe injury for his goals. His notable abilities center on ki manipulation, taught through the Takayanagi clan's martial arts. He masters Uraate, a fulcrum-based transference skill that allows him to shift the point and force of impact through any medium. His clan's ultimate secret, Ryuukei Qigong Tashinkou, lets him compress rotational force into a needle of ki and launch it through the air as a devastating punch. He also employs Hakka Soudou Shou, a double palm strike that transfers immense momentum, and Shin'irikugou Bateihouken, a horse-style punch aimed at the heart that can cause cardiac arrest. His specialization as an anti-weapons fighter gives him an edge against opponents reliant on blades.