Religion

Religion plays an important role in Emperor. Heroes are associated with one of the 4 religions, and to get a hero to your city, you need to have the proper religious buildings in your city. Religion buildings are also needed to upgrade your housing.

Diviner - Ancestral Shrine
Diviners from an Ancestral Shrine satisfy the most basic religious needs of your citizens. Without a shrine, you can't pay homage to Ancestral Heroes, and they will get angry after a year or three without homages.
Priest - Daoist Shrine and Temple
Priests from Daoist Shrines and Temples provide access to Daoism to your houses. Daoism is later replaced by Buddhism, although both are generally available. At least one Daoist temple is needed to pay homage to a Daoist hero, and to get such a hero to your city. Temples send out two priests, while shrines only send out one, but generally that doesn't have a real benefit.
Monk - Buddhist Shrine and Pagoda
Monks from Buddhist shrines and pagodas provide access to Buddhism to your houses. Buddhism kind of replaces Daoism in the later periods, but daoist buildings generally remain available. Houses only need access to one of both to evolve to the higher levels. At least one Buddhist Pagoda is needed to pay homage to a Buddhist hero and get them to your city. Like with Daoist buildings, a pagoda sends out two walkers, and shrines only one.
Scholar - Confucian Academy
After the Confucian Academy has been supplied with either wood or paper, scholars emerge from it to teach the children of the nobles. Only rich people need this education, so it has no use to place an Academy in your common housing block. You need to have at least one Confucian Academy to pay homage to Confucian heroes.

Tips on religion

If a daoist shrine isn't harmonious (Feng Shui) in a certain location, you might want to place a buddhist shrine in its place (if both are available). Houses only need one of the two to evolve to a higher level.

If you want a certain hero to appear in your city, and you want to give homages as efficient as possible, be sure ALL citizens have access to that particular religion. The exception here is the Confucian Academy: only all of your elites need to have access to confucianism for your homages to be as effective as possible.

Historical information

The following information is from BreakAway.

Ancestor Worship

From its ancient beginning, Chinese culture has been based on ancestor worship. According to this view, the deceased can influence the welfare of the living. By showing proper respect and honor to one's ancestors, the ancestors can spiritually intervene with heaven and help bring harmony to the family. This is a reciprocal relationship where each side depends on the other, and each side benefits from the other.

In addition to ancestor worship, the Chinese have been blessed with the "Three Ways" of Confucianism, Daoism and Buddhism. Unlike the Western religious practice of exclusivity, where adherents of a faith ignore other faiths, the man-on-the-street in ancient China often accepted aspects from multiple religions, seeing in each of them a valid way to a greater truth. Unfortunately, there were also periods of religious intolerance and persecution in China, but over all, these "Three Ways" along with ancestor worship became the religious cornerstones of Chinese culture.

Confucianism

Confucius (551-479 BCE) is the most famous person in Chinese history. His ethical philosophy became the basis for Confucianism, one of China's three great religions. The Analects is a compilation of his sayings, written by his followers after his death. From the Han dynasty onward, officials studied Confucian classics and applied its moral code to government. Candidates to officialdom had to study and practice many years for any chance of passing the imperial exams, which required lengthy memorization of the classics.

Daoism

Lao Zi (6th century BCE) is credited with writing the Dao De Jing, which contains the basic principles and philosophies of Daoism. Daoism emphasizes the balancing principles of yin and yang, and the search for longevity and serenity.

Buddhism

Buddhism was introduced to China from India around the 2nd century CE. The Chinese adopted and modified Buddhist thought to fit their own view.