Wikipedia
Yiguandao , meaning the Consistent Way or Persistent Way, is a Chinese folk religious sect that emerged from the Xiantiandao ("Way of Former Heaven") tradition in the late 19th century, in Shandong, to become China's most important redemptive society in the 1930s and 1940s, especially during the Japanese invasion. Another name of the faith is Zhenli Tiandao ( "True Order of the Heavenly Way") or simply Tiandao (, "Way of Heaven"). In the 1930s Yiguandao spread rapidly throughout China led by Zhang Tianran, who proclaimed himself as the eighteenth patriarch of the Xiantiandao lineage, among thousands of other sects that thrived since the collapse of the Qing dynasty in 1911.
In the 1930s Yiguandao was a local religion of Shandong with a few thousand followers, but under Zhang Tianran's leadership and with missionary work the group grew to become the biggest sect in China in the 1940s with millions of followers. After 1949, Xiantiandao sects were proscribed as illegal secret societies and heretical cults. While still banned in China, Yiguandao was legally recognised in Taiwan in 1987 and has flourished since then.
Yiguandao is characterized by an eschatological and soteriological doctrine, presenting itself as the only way to salvation. It also encourages adherents to engage in missionary activity. Yiguandao is the worship of the source of the universal reality personified as the Eternal Venerable Mother, or the Splendid Highest Deity as in other folk religious sects. The highest deity is the primordial energy of the universe, identified in Yiguandao thought with the Tao in the wuji or "unlimited" state and with fire. The name used in contemporary Yiguandao scriptures is the "Infinite Mother" and the "lantern of the Mother" —a flame representing the Mother—is the central focus of Yiguandao shrines.