A tripartite between the states of:
Wei (魏) Shu (蜀) and Wu (吳)
followed the loss of the de facto power of the Han dynasty in China. As a result, it ushered in the start of the Period of Disunity.
Wei is also known as Cao Wei (曹魏), Shu is also known as Shu Han (蜀漢),and Wu is also known as Dong (or Eastern) Wu (東吳).
The Three Kingdoms period is one of the bloodiest in Chinese history.
In fact, it has been considered the second deadliest period of warfare behind World War II. A nationwide census taken in CE 280, following the reunification of the Three Kingdoms under the Jin shows a total of 2,459,840 households and 16,163,863 individuals which was only a fraction of the 10,677,960 households, and 56,486,856 individuals reported during the Han era.