Sect leader: Li Hongzhi
The Fa Lun Gong movement promises to cure sickness and reverse a tide of evil sweeping mankind to the brink of catastrophe.
It is one of numerous cults and folk religions which, along with more traditional beliefs such as Christianity and Buddhism, are filling a spiritual void in society as China abandons socialism.
"Your diseases will be eliminated directly by me," leader Li Hongzhi, 47, wrote in one of his five books, regarded by devotees as sacred.
Some followers believe the end of the world is near.
Mr. Li's cult claims more than 100 million members and sees human corruption in everything from homosexuality to rock music and drug addiction.
His teachings hark back to ancient Chinese civilization before the advent of modern science, medicine and technology.
He claims power of healing from the Chinese martial art form of qigong, whose practitioners tap into an "inner energy".
The Fa Lun Gong - or "Buddhist Law" cult - is rooted in the notion of karma, which holds that people's good and bad deeds determine their fate in the next life. Society is in such steep decline that humans are actually being reincarnated as demons, many disguised as monks, according to Mr. Li, who lives in Houston, Texas, devotees said.
"Especially in Taiwan, many famous monks or lay Buddhists are actually demons," he wrote.
Other qigong masters in China were "possessed with foxes or yellow weasels, and some with snakes".
Although the Fa Lun Gong is anti-science, members use the Internet to propagate Mr. Li's teachings.
It appears to be tapping into deep public resentment, and fear of the unknown, as China undergoes wrenching social change and upheaval in its march to capitalism.
Hou Huilan, a 55-year-old factory worker at yesterday's demonstration, said Mr. Li's teachings had taught her lessons in family values and civic virtues.