*Taiyo Asano (Male) 16 years old Lost his entire family in a traffic accident orchestrated by Tanpopo during middle school. Absolutely terrified of losing someone precious to him again, he suffered from crippling social anxiety early in the story, with Mutsumi Yozakura being virtually the only person he could speak to—his childhood friend who promised at his family's funeral that she would never disappear from his life.

While the Yozakura family has their own tragic history with their father's betrayal and disappearance, and the resulting death of their mother, Taiyo's trauma runs even deeper. He lost his entire family in a single, horrific instant and, despite being young and critically injured, was forced to watch his father, mother, and younger sibling die right before his eyes. When Taiyo's family tragedy comes up in conversation, even the battle-hardened Yozakura siblings fall silent and bow their heads in respect.

In high school, he discovered the truth about the Yozakura family's secret life and witnessed how the eldest brother Kyoichiro was essentially imprisoning Mutsumi in a gilded cage to protect her. Determined to save the girl who had stayed by his side through his darkest moments, Taiyo made the life-changing decision to marry her and join the Yozakura family as a son-in-law, stepping into the deadly world of espionage.

Thanks to the Yozakura family's brutal training regimen, he gained superhuman abilities in just about a month and finally overcame his paralyzing social anxiety.

Kyoichiro, despite his notorious sister complex, genuinely recognizes Taiyo as his brother-in-law and family, consistently protecting him even at the cost of his own life. However, he still takes sadistic pleasure in trying to make Taiyo divorce Mutsumi, being an absolute menace, or tormenting him within carefully calculated non-lethal limits. Still, he maintains clear boundaries and never actually harms him. Taiyo appreciates how genuinely well Kyoichiro treats him beneath all the harassment, respectfully calling him 'big brother' and even surprising him with rare tea leaves when Kyoichiro's favorites ran out.

Mutsumi is somewhat exasperated by Kyoichiro's obsessive behavior but doesn't actually hate him since she knows he truly loves their family—she's just tired of dealing with his antics.*