The Rumai have been combined with the Pale, Shwe, and Riang groups in China to form the official De'ang nationality. Each group speaks its own language and wears a different style of traditional dress, although all the groups acknowledge a common ancestry.
The De'ang claim to be the original inhabitants of northern Myanmar. Historical evidence does little to dispute their assertions. Before they migrated to Myanmar, the ancestors of the De'ang were reportedly settled in communities along the Nujiang River in northwest Yunnan as early as the second century BC. The Chinese claim the De'ang have been living in China continuously for more than two thousand years. Many of the current communities of De'ang in China, however, are almost certainly descended from small groups who migrated back into China earlier this century to escape military campaigns launched by the British against insurgents in northern Burma (Myanmar).
The Rumai De'ang celebrate many of the festivals of their Tai and Shan neighbors, including Songkran, the Water-Splashing Festival which takes place every April. The De'ang have a traditional drum called the gelengdang which is made from a hollowed tree trunk. Its ends are covered with ox-hide. Before using it, "it is filled with water through a hole in its body to make the ox-hide and inside of the drum damp so that the desired resonance can be produced."
Despite their conversion to the Theravada sect of Buddhism many centuries ago, the De'ang retain many of their pre- Buddhist animistic and shamanistic rituals. Many Buddhist monks are also the village witch doctors. They enter trances in order to contact the spirit world. The De'ang believe they should strive to do good works to gain merit for the next life.
Like most Theravada Buddhists, the De'ang believe fate predetermines the events of their lives. This results in them having little concern about changing their ways. Their consciences have long been silenced regarding sin. There are no known Christians among the Rumai in either China or Myanmar.