2K-tan is a moe anthropomorphism of the Microsoft Windows 2000 operating system, featured in the OS-tan series. She is depicted as a mature, responsible, and serious young woman, often seen as a caretaker for the other OS-tans. 2K-tan is known for her professional attire and glasses, reflecting the stability and reliability associated with Windows 2000. In the series, she frequently acts as a mediator and support figure, helping resolve conflicts among the other OS-tans with her calm and level-headed demeanor.