Buddhism in Japan began teaching devotion to the "Lotus Sutra". Eventually, his disciples formed their own school of Nichiren Buddhism, which includes various sects that have their own interpretations of Nichiren's teachings. Nichiren Buddhism established the foundation of Japanese Buddhism in the thirteenth century. The school is known for its sociopolitical activism and looks to reform society through faith. In the Muromachi period, Zen, particularly the Rinzai school, obtained the help of the Ashikaga shogunate and the Emperor of Japan, and accomplished considerable development. After the Sengoku period of war, Japan was re-united in the Azuchi–Momoyama period. This decreased the power of Buddhism,
Faith in Buddhism bird-like deities and violent spirits which previously were the focus of pre-Buddhist cults became guardians of the Buddhist teaching. This process of adopting deities as part of Buddhism often occurred when Buddhist devotees or monks did not fully renounce their former devotions when embracing Buddhism. In the early Pāli scriptures, as well as in some customs in traditional Buddhist societies, traces can still be found of the period that Buddhism competed with "nāga" worship and assimilated some of its features. In some Buddhist countries like Japan, a perspective arose of the human world as a microcosm of the macrocosmic realms