While few written sources mentioned Phật Trùm, on the contrary, the life and deeds of Bổn Sư, or True Eremite, have been better documented. Bổn Sưs lay name was Ngô Lợi, while he was also known as Ngô Viên and Năm Hữu. Some of his followers believed that Bổn Sư possessed certain supernatural abilities. For instance, when he seemed sleeping his soul was believed to travel elsewhere. Therefore Bổn Sư acquired a reputation of a master of trances, or thiếp, hence he was widely known as Năm Thiếp.
There have been conflicting reports concerning his birthplace. According to some sources, Ngô Lợi came from the frontier areas near the Cambodian border. It was also reported that he was born in Trà Tân village in Mỹ Tho province near Saigon. Ngô Lợi reportedly assumed the Bổn Sư title in 1870. However, Hiếu Nghĩas sutra of the Bửu Sơn Kỳ Hương tradition stated that Ngô Lợis accession to religious prominence actually took place in 1879. According to Bửu Sơn Kỳ Hương tradition, Ngô Lợi experienced a sudden religious enlightenment. Subsequently, he practiced healing and exclusively used cold water for the purpose. Hence it might be argued that Ngô Lợis healing practices were well in line with the evangelizing patterns set by Tây An.
Notably, in February 1878, Ngô Lợi convened some 200 monks for a “vegetarian festival” in Hòa Khánh village, Mỹ Tho province. In fact, it was a secret gathering designed to discuss an upcoming revolt against the French colonial authorities. Ngô Lợi named one of his supporters, Kha, as a chief officer and Ong as a deputy. They were ordered to stage a rebellion in the Mỹ Tho area in April 1878. However, somebody tipped the French police and both Kha and Ong were arrested by Trần Bá Lộc, an official of the French administration. Moreover, Trần Bá Lộc also offered a sizable reward of 1,000 piasters to anyone who could help apprehend Ngô Lợi, the mastermind of the failed revolt.
Yet despite this setback, Ngô Lợi did not abandon plans to oppose the French authorities. In the wake of the failure of the Kha and Ong rebellion, Ngô Lợi reportedly negotiated a tactical alliance between Vietnamese and Khmer anti-French resistance fighters led by Prince Si-Vatha. In May 1885, the allied rebel forces seized a French outpost in Phú Thạnh. It was a serious incident because the French were forced to bring in reinforcements of 200 troops in order to regain the outpost. However, French retaliation ensued. In response, in May 1887 the French military launched a massive assault against An Định settlement and detained 1,990 settlers. However, the French failed to apprehend Ngô Lợi.
It should be pointed out that during the first years of the French conquest many agricultural settlements fell apart and were destroyed in the South due to the general situation of disorder. Correspondingly, many centers of Bửu Sơn Kỳ Hương worship were badly hit and the sects followers dispersed throughout Mekong Delta. This is why Bổn Sư was keen to gather them and found new settlements in areas, which were seen as less vulnerable to possible French attacks. Notably, Ngô Lợi set up An Định village near Thất Sơn, or the Seven Mountains, area. When the French finally arrived to destroy An Định in 1887, it was a thriving rural community and nearly two thousand settlers lived there.