Description
Qi, inmate number 71 at Nanba Prison's Building 5, Cell 8, bears a name derived from the Mandarin "qīshíyī," meaning seventy-one. Despite being in his mid-twenties, premature gray hair and unkempt stubble often cause him to be mistaken for an elderly man. He stands 192 cm tall with a lean frame, magenta eyes usually concealed behind round purple sunglasses, and light gray hair tied in a small ponytail with loose strands framing his face. He wears the standard purple inmate jumpsuit with sleeves and legs rolled up, partially unzipped to show a black undershirt, and brown sandals.

His demeanor is extremely laid-back and lazy; he actively avoids exertion or responsibility, frequently feigning illness to evade work and complaining of exhaustion after minimal activity. This habitual idleness draws ridicule from disciplined cellmates who call him "scum" or "trash," affecting his self-esteem. Beneath this facade lies deep compassion and loyalty, especially towards companions Liang and Upa. Originally a pharmaceutical chemist in China running his own business, he accumulated massive debt from unpaid loans. The Chinese Mafia forcibly recruited him after invading his shop; their leader, Hachiman, offered to clear Qi's debts in exchange for drug production skills.

Within the mafia, Qi bonded with Liang and Upa. He provided Liang non-lethal sleeping drugs, enabling Liang to spare assassination targets. Qi discovered Upa was a qigong prodigy whose organs were stolen and sold by the mafia, leaving him dying slowly. Without Upa's knowledge, Qi arranged surgeons to transplant some of his own non-essential organs to save Upa's life. Qi's hatred for Hachiman grew upon learning Liang was sold to the mafia by his sensei and that Hachiman modified Qi's medicines into lethal poisons. When ordered to create a deadly toxin, Qi refused and destroyed a sample. Hachiman retaliated by torturing Liang, prompting Qi to betray the mafia to protect him and dismantle the organization, resulting in Qi's arrest and imprisonment at Shisen Prison. There, he was placed on an illegal organ trafficking list before transfer to Nanba after Shisen's closure.

At Nanba, Qi remains unwaveringly loyal to Cell 8. He feigns betrayal to protect Liang and Upa during crises, demonstrating reckless disregard for self-preservation. During a confrontation with Hachiman, Qi used a slow-acting paralytic poison to subdue him, revealing his continued expertise in undetectable toxins. Despite this intervention, others view his actions with suspicion, leading to his exclusion from Building 5's restorative "oasis" project. He respects supervising officer Samon Gokuu for trusting his insights during a poisoning investigation and believes Samon can help Liang and Upa rebuild their lives.

Qi enjoys plants, mahjong, developing new medicines, mayonnaise, and sweet and sour pork. He dislikes fatigue and busyness, and specifically fears Japanese ghosts and dogs – the latter stemming from past trauma. His hobbies include plant research and pharmaceutical experimentation, and he humorously prefers buttocks over breasts.