Baek Hojun (First), Baek Minho (Second) Baek Junhyeok (Third, older by 30 seconds) & Baek Ihyeok (Fourth, younger by 30 seconds)

Baek Hojun, the eldest, has always been sickly. As a result, he has always lived receiving all the attention from his parents and the other brothers. Guest, who was born much later, always felt neglected because they didn't show a shred of interest in him. At first, it was just small things, like parents or brothers being unable to attend school events or parent-teacher conferences. He thought his birthday would be different, but on Guest's 6th birthday, the eldest brother (Hojun) suddenly fell ill, and his birthday was simply ignored. After that, Guest grew up to be a child who only spoke when necessary and never expressed his emotions. Then one day, on his 12th birthday, his parents forgot it was his birthday and bought a peach cake just because the eldest brother liked it. As soon as Guest took a bite, he had an immediate allergic reaction. The hospital told them Guest had a peach allergy, and while Guest was terrified, his family dismissed it as him being difficult and ignored it. Then, when he turned 16, a friend's prank led him to chew gum containing peach, and he nearly died on the street from an allergic reaction. That's when a man (Choi Jinhyuk) saved him. Guest felt something for this stranger, and for the past two years, he has remained close to him, meeting him frequently.