Four Gods

The Four Gods (四神), also known as the Four Symbols (四象), Four Sacred Beasts (四聖獣), Four Spirits (四霊), are deities that reign over the cardinal directions of the constellations. A fifth god, the Yellow Dragon, is also said to rule the center. These gods are particularly famous throughout Eastern Asia and appear in a variety of fictional works.

Names and Traits
A dragon is considered the benevolent and powerful ruler, promising good fortune and fertility. Qinglong is known for its particularly long tongue, which curves and twists in several portraits. Though associated with the color blue, it has also been argued to have once been known as the "green dragon" ages ago.

The majestic bird held a noble behavior and was picky about what it eats and where it perches. Zhuque has often been confused with a phoenix due to their similar appearances and has been said to either be a red sparrow or a fenghuang.

Tigers were considered to be the king of all beasts in China, and white tigers were mythic elder versions of tigers. A white tiger is said to only appear when the world is at peace or if the Emperor ruled with virtue. It's fabled that Baihu is either the eldest or youngest of the four beasts.

The tortoise and the snake were symbols of longevity in China and were symbols of honor with a similar meaning in Japan. The word "tortoise" could also mean "taboo" in Chinese. Xuanwu is sometimes depicted as a turtle with a serpent for its tail. It's also associated or argued to be another form for Emperor Xuanwu, an individual who is depicted in black robes and appears as an entity within Journey to the West.

For universal simplicity, they are also translated as the color they represent and their beast (i.e: Black Tortoise for Xuanwu). In Japan, these gods are known as Seiryuu or Seiryō (Qinglong), Suzaku or Sujaku (Zhuque), Byakko (Baihu), and Genbu (Xuanwu). These four beasts are additionally part of the Twelve Saintly Generals named by the famous onmyōji, Abe no Seimei.

Many games from Koei add small references to these gods for items or weapons, especially for their China based works like the Dynasty Warriors series or Mystic Heroes.

Harukanaru Toki no Naka de
The Harukanaru Toki no Naka de series refers to the four gods as four sacred beasts. They have some slight differences than their mythological counterparts, listed in the chart below.

The protagonist of each game communicates with each sacred beast in person. Each god will then request the priestess's interpretation of the trait they represent and will agree to serve her after hearing her answer.

History
The series' universe establishes the four sacred beasts as servants of the White Dragon, the divine entity who chooses the series' protagonists as his destined priestess. Along with the White Dragon's opposite, the Black Dragon, these gods help protect the parallel world in their respective directions and oversee the proper flow of the Five Elements. Another servant of the White Dragon, the White Kirin, once served a similar purpose long ago and was designated as the leader of the four gods. Like the White and Black Dragons, the White Kirin also had its counterpart, the Black Kirin. However, the Kirins do not appear in later eras of the series's history (Black Kirin makes another appearance in the first game).

Long ago, the four sacred beasts resided within designated caverns and would appear if the chosen ones they desired summoned them. Skeptic of mortals, however, each required a test of their mettle before agreeing to join them. In Suzaku's case, he was berserk from a cursed chip of his seal and thanks the mortals for restoring him. He also resided within an ancient flying ship, which the protagonist can use to fly to various parts of the parallel world.

About a hundred years before the first game of the series, these gods primarily protected the capital. Whilst there, they are aided by the divine protectors of the city gates. These protectors were conjured by a famed sorcerer who tied these entities to the four gods. To fully unite the four gods, the support of these guardians were essential. When the Demon Clan tried to take over the capital during the first game, the dormant four sacred beasts were placed under curses and used against their will by the demons. Once these curses were lifted, the four gods resumed their services. They returned to their slumber after the priestess performed her duty.

During the second game, the four sacred beasts would only grant their divine protection to their respective Eight Guardians (see below). Others parties would try to take their seals by force yet the gods did not answer them. When the priestess of this age wishes for the twin dragons to extend their mystic protection across the parallel world, the four gods also act in accordance for her peaceful desire.

One century after the priestess's wish, Taira no Kiyomori attempts to manipulate the White and Black Dragons to bend to his will, disrupting the flow of the Five Elements. Causing an upsetting disturbance within the capital by his actions, Musashibo Benkei infiltrates the Heike household at Rokuhara and destroys the dragons' physical forms at the time. He foils Kiyomori for the moment but unintentionally plunges the world into further corruption. The four gods and their guardians are scattered once more, an infant White Dragon is born to replace the previous one destroyed, and the severely weakened Black Dragon is placed under a curse and entrapped against his will. While they obey the priestess's will, the four gods may express discontent to their new White Dragon, deeming him too weak and inadequate to lead them.

Though they are known to protect the parallel world, these gods occasionally appear in different dimensions to serve the priestess. They manifest themselves within a mirror world for her, can be seen residing within books in a mystical labyrinth, or appear within the series's dream world in their respective directions.

Eight Guardians
The Eight Guardians (八葉, Hachiyou, literally translated as the Eight Leaves) are defenders and servants of the White Dragon Priestess. They are chosen by the White Dragon, the proof being the Dragon Gems (龍の宝玉, Ryu no Gyoku) on their bodies that can mainly be seen by the priestess and other guardians. As avatars for the four sacred beasts, they are split as either the Heaven (天, ten) or Earth (地, chi) for a single god. Each guardian represents a placement within the Five Elements and have an innate element associated with them. These traits are shared with all designated guardians in the first three games; they partially influence characters within the fourth title.

Eons ago, the Dragon Gems were originally gems associated with the royal family of Nakatsu Country. The princess of the same country would obtain them during the war with Tokoyo Country. When she proves the worth of humanity to the White Dragon, he associates these gems to traits of the human heart inspired from the eight warriors guarding her. These gems later appear as a part of future guardians.

A priestess's strength is parallel to the hachiyous trust in her. If she is too weak, they won't serve her or believe in her. The hachiyou also need to trust in each other, for their true potential is demonstrated only when they unite their will as one. While being together adds protection for the priestess, they do not always have to be physically near one another to have the same effect. So long as the bond with a priestess and her hachiyou is present, they will never be truly separated.

Once the priestess gains the gods' trust, guardians can summon them in battle to attack foes. The first three titles allow the guardians of a single god to also invoke their divine aids, though the respective Heaven and Earth guardians need to be together to perform the incantation. The two warriors who have the god's protection are required to summon a beast into the field in the fourth title.

The fifth title seems to imply that guardians no longer have the Dragon Gems visible on their bodies.