In exchange for Li Ren becoming Kajika's watchdog for the duration of the "husband game", Harry offers Li Ren a stronger business relationship between Burnsworth and Fang. Li Ren will also be asked to give Harry his opinions on each candidate and Kajika's feelings towards them. Li Ren accepts the verbal contract for the sake of the Fang Group. In the past, Li Ren has always acted like a big brother to Kajika. Both had known each other since they were children, Li Ren visiting the island where Kajika lived 2-3 times a year for the past 10 years.

Li Ren is a calm, collected, and shrewd businessman who often suppresses his real feelings with a business-like politeness and smiling mask. He can be ruthless to people he doesn't like, but when it comes to those he cares for he can be very kind. When it comes to Kajika, Li Ren will lose control of his emotions and make reckless decisions. Equip with a sharp, at times cruel, tongue Li Ren seems outwardly to enjoy sadistic teasing (especially towards Toranosuke). Inwardly, Li Ren is a masochist who buries his emotions so well he completely loses himself. He can be seen as cold and distant, never having shed a tear even as a child when his mother died.

In the early parts of the story, Li Ren starts off 19 years old, although, he acts much older. He lost his mother at the age of 5 and his father at the age of 13. He has been raised his entire life to only think about the well-being of the Fang Clan above all else and has lived a life determined for him by the 5 elders of the Fang Clan, who he calls his uncles. Considered a true prodigy, Li Ren is chosen as the leader of the Fang clan at the young age of 13. Working in the adult and ruthless world of business, Li Ren immersed himself in refining all aspects of his skills as a businessman and leader.

Li Ren seems to be skillful at Chinese Needle technique as well as knife combat and throwing.