Retto Enjō, a high school student with short wavy red hair and a lean yet muscular frame accentuated by a defined six-pack, blends determination, protective instincts, and leadership while upholding a respectful demeanor. His combat role involves channeling sexual energy (H-energy) against Censor Bugs—aliens draining humanity’s vitality—despite the non-perverted ethics guiding his actions. Recruited into the HxEros team by his uncle Jō Anno, his resolve stems from a childhood trauma: witnessing Kirara Hoshino, his lifelong friend and eventual romantic partner, emotionally shattered by a Censor Bug attack. Her subsequent withdrawal fueled his commitment to protect Earth, even as he sought to mend their fractured bond.

Retto’s combat prowess centers on H-energy, drawn from arousal to power his team’s battles. These clashes frequently destroy clothing, necessitating spare outfits mid-mission. A perilous "Beast Mode" activates when Chacha, a reformed Censor Bug ally, bites him, flooding his system with uncontrollable H-energy. This state erodes his rationality, driving aggressive pursuit of nearby women—a risk the team judiciously avoids to uphold moral boundaries.

Interpersonal ties shape his journey. Kirara’s icy distance post-attack challenges Retto’s persistence, yet their bond gradually thaws, culminating in mutual love and commitment. His younger sister Hiiro and teammates—Momoka Momozono (whose quiet affection lingers unspoken), Sora Tenkūji (prone to sleepwalking into his bed), and Maihime Shirayuki (unintentionally drawing his focus due to her potent H-energy)—anchor team dynamics through collaborative missions and accidental intimacy.

Retto’s growth navigates reconciling Kirara’s trauma, leading the HxEros team, and balancing personal ethics with H-energy’s volatile demands. The narrative resolves with a ceasefire brokered with the Censor Bug Queen and his romantic clarity with Kirara, though lingering threats demand vigilance. Themes of perseverance, emotional honesty, and sexuality’s transformative power against existential crises underscore his story.