The Lungmenite Perro named Ko Hei-sing was originally a security guard of a company who was fired due to his rather friendly yet timid character. In the midst of his misery and hunger, he coincidentally encountered Mr. Lee and was brought under the care of the Lee's Detective Agency. Within Mr. Lee's close-knit "family," Ko plays the role as their chef thanks to his cooking skill and a guardian for young Waai Fu and Aak.

(Source: Arknights Wiki)