TV-Series
Description
Naoya Mukai is a high school student defined by extreme straightforwardness and persistence in actions and beliefs. His personality remains explicitly consistent regardless of situation, frequently resulting in socially unconventional behavior. This manifests as an absolute refusal to lie or conceal truths, even when socially disadvantageous, driven by a personal moral code prioritizing radical honesty over practicality.

His background includes a longstanding romantic pursuit of Saki Saki beginning in elementary school. He persisted with monthly confessions across nine years of rejections, finally securing her agreement to date upon entering high school. Shortly after, classmate Nagisa Minase confessed her feelings. Unable to dismiss her sincerity and impressed by her dedication, he proposed dating both simultaneously, securing Saki's reluctant permission. This established a two-timing relationship where all three lived together in Naoya's residence, his parents absent for unspecified work reasons.

Naoya displays dichotomous traits: pursuing multiple relationships while showing self-awareness of the emotional burden on his partners. His determination manifests in protecting the polyamorous arrangement, rejecting third parties like Rika Hoshizaki despite her advances. However, this resolve later evolves; he accepts Kiryuu Shino as a third girlfriend following her confession, initially to accommodate Saki's wishes, and later Rika as a fourth. He admires hard work and dedication, qualities attracting him to Nagisa and compelling him to defend Rika's creative efforts when her father threatened her online channel. Academically serious, he prioritizes studies during free time, tutors others diligently, and values educational achievement, though he rarely ranks top in his class.

Physically, Naoya is tall with medium-length black hair (depicted as brown in some adaptations) and gray eyes, frequently wearing a standard school uniform. Personal details include a December 31 birthday, a liking for bananas, and aviophobia.

His character development reveals increasing emotional complexity. Initially insisting on limiting relationships to two girlfriends, he gradually accepts Shino and Rika, signaling evolving perspectives on commitment. He experiences profound guilt over polyamory's challenges, culminating in tearful frustration over perceived failures in making all partners happy, driving greater collaborative efforts. His chivalry includes refraining from non-consensual physical contact despite suggestive situations and supporting Saki's hypothetical two-timing. Rika initiated his first kiss, followed by subsequent kisses with all primary heroines.

His name's etymology reflects his personality; "Naoya" combines "straight/direct" (直) and "to be" (也), while "Mukai" implies "confrontation" or "approach" (向井).