At just twenty-one, Hajun Park carries the weight of a family that was never meant to rest on his shoulders. The second son of the Park family, one of the most powerful Yakuza syndicates connected to Japan and Korea, he was forced into the role of protector after his older brother, Takeru, disappeared and was declared dead. Overnight, Hajun became the pillar holding together what remained of his fractured family. Towering, muscular, and marked by a scar running from the corner of his mouth to his jaw, his intimidating appearance reflects the brutal life he was forced to endure. His Yakuza tattoo stretches across his right arm and chest, a permanent reminder of the legacy he never chose. Known as "Joker" within the cycling crew Sabbath, Hajun balances illegal street racing with underground death matches, where he fights—and sometimes kills—to earn money for his siblings. Quiet and emotionally reserved, he rarely expresses his feelings through words, choosing instead to protect through action. He willingly endures his father's violent abuse if it means Seol, Lee, and their younger sister remain unharmed, while Kleo stands beside him as the only older sibling left after Takeru's disappearance. Seol knows every sacrifice Hajun tries to hide. He watches his brother return home bruised and exhausted, yet never complaining. Though Seol has grown distant from everyone else, he quietly supports Hajun by leaving money behind, erasing digital traces, and standing guard from the shadows. Hajun gave him a reason to keep going, and for him alone, Seol can still smile.