Short answers, pulled from the story.
Shinto, also called Shintoism, is a polytheistic and animistic religion originating in Japan that revolves around supernatural entities called kami. Kami are believed to inhabit all things, including forces of nature and prominent landscape locations such as waterfalls, mountains, and large rocks. The religion has no single founder, no central authority, and no single canonical text.
There are around 100,000 public shrines in Japan, found everywhere from isolated rural areas to dense metropolitan ones. About 80,000 are affiliated with the Association of Shinto Shrines, while another 20,000 are unaffiliated. A public shrine is called a jinja, meaning kami-place.
Several scholars argue that Shinto as a distinct religion was essentially invented during the nineteenth century Meiji era, when Japan's nationalist leadership expelled Buddhist influence from kami worship and formed State Shinto. The historian Kuroda Toshio noted that before modern times Shinto did not exist as an independent religion. Kami veneration itself has been traced back to Japan's Yayoi period, from 300 BCE to 250 CE.
Shinto places a major conceptual focus on avoiding kegare, meaning pollution or impurity, while ensuring harae, or purity. Pollutants include death, disease, incest, and blood from menstruation or childbirth, and they are removed through purification rites such as misogi, which uses fresh water, salt water, or salt. Full immersion in the sea is often regarded as the most ancient and effective form of purification.
Shinto priests are known as kannushi, meaning proprietor of kami, and many inherit the role through specific families. They are trained at Kokugakuin University in Tokyo and Kogakkan University in Mie Prefecture, and are assisted by jinja miko, sometimes called shrine-maidens, whose most important role is the kagura dance. By the late 1990s, around 90 percent of priests were male and 10 percent female.
The Yasukuni Shrine in Tokyo is devoted to Japan's war dead and is especially controversial because in 1979 it enshrined fourteen men who had been declared Class-A defendants at the 1946 Tokyo War Crimes Trials. The enshrinement generated domestic and international condemnation, particularly from China and Korea.
Shinto is Japan's largest religion and Buddhism is the second, and most of the country's population takes part in both, especially festivals. The scholar Brian Bocking noted that most Japanese people are still born Shinto yet die Buddhist, since funerals tend to take place at Buddhist temples. This reflects a common Japanese view that the beliefs and practices of different religions do not need to be exclusive.