Onryou

Onryou (怨霊; literally "resentful" or "vengeful spirit") is a type of malevolent spirit found in Japanese folklore. Onryou differ from ghosts due to their creation, which is caused by an unclean death. Premature deaths due to war, murder or illness are prime onryou candidates. They may or may not even remember how they perished.

Onryou are spirits that roam the earth with anger towards the living. They are envious of human flesh and will not leave their haunting spot until their resentment is resolved. Their intense grudges and unyielding hatred make them a common feature in Japanese horror stories.

During the Heian Period, people were mostly afraid of the "Onryou" because they believed that these spirits could cause chaos, plagues, and oblivion. At first, they thought that onryou were invisible spirits that could float above those who disgusted them. Heian Period folklore insisted they were able to attach their soul to a momentary vessel, sometimes acquiring a dilapidated shape for their vapor image. Based on the era's beliefs, various evil spirits such as Fuujin and Raijin could be classified as onryou, though their exact resentment for the living would be unknown.

Role in Games
Onryou serve as the main enemies within the Harukanaru Toki no Naka de series. The games have them behave in a similar manner as actual Japanese folklore, onryou being departed spirits. However, other types of spiritual creatures in folklore may terrorize the land as onryou. A few of which includes tengu, nue and kitsune. Each onryou may choose a specific location to haunt or may be a random encounter on the overworld map.

Earlier titles may have onryou regenerate once they are defeated. In order to completely eradicate them, the player will need the ability to seal (封印, fuuin) them. The sealed onryou then become talismans for the main party to equip, increasing allies' various strengths. When a White Dragon Priestess seals an onryou, she may recite the following chant: "Assemble, Heaven's voice! Resound, Earth's voice! Seal those before me!"

When onryou are purified by the priestess's chant, their negative form will disappear. A floating spirit eventually negates its hatred and merges to become one with the Five Elements. The added elements can then nurture the parallel world. If a spirit was at peace at the time of the purification, their soul may either rest in the afterlife or return to the natural cycle of reincarnation. A particularly mighty onryou can resurrect any onryou against their will, regardless of whether or not they were purified. The priestess can then seal the "leader" onryou to grant peace towards every spirit.

Usually onryou are depicted as wild beasts with no consciousness, only capable of destruction or tarnishing the land with other spiritual corruptions. When they are loose for prolonged periods of time, they may become capable of devouring humans caught within their grasp.

To counter the negative effects, Kiyomori destroyed one of the Three Sacred Treasures, the Yasakani no Magatama. Although shattered, the gem retains a powerful spiritual energy that helps retain the sanity of any onryou holding it. Departed spirits can then materialize and sustain their human self, essentially granting the bearer a second chance at life. Nothing can be done to completely negate their violent nature, however, so they risk losing their remaining humanity if they become too cocky of the gem's neutralizing effects.

About four hundred years after the parallel world's Heian period, onryou are a deformity which arises in the absence of the dragon gods' protection. These gods have become too weak to bring back order, resulting in the parallel world being filled with these monstrous spirits. As the parallel world crumbles, its spiritual connection with the modern world grows stronger, enabling the onryou to cross over. These onryou mainly haunt Japan and are not known to exist in other parts of the world.

Kagerou
During the parallel world's Bakumatsu, another spiritual irregularity emerges due to the misalignment of the Five Elements. They are called kagerou (陽炎), and they are the souls of individuals who held onto a strong wish before their death. They haunt the mortal realm with regrets of their previous life, demanding to see their final dream made a reality. Many men who are killed because of their beliefs emerge once more as kagerou.

Kagerou can also be summoned as tools of war by people with strong spiritual capabilities. They need only to place a seal on the kagerou to properly direct them. The kagerou will instinctively believe that the target is an obstacle to their dream and will initiate their berserk rampage. Once the warriors have served their purpose, the caster can recall the seal to instantly remove the hateful spirits.

Unlike onryou, kagerou retain their human appearance before their death. If they are defeated in combat, they might verbally plead their case with what little sentience they have left. They appear so lifelike that it may cause people to doubt if they are truly dead. Yet it is impossible to resurrect them. Only the priestess's purification can lay their wrathful souls to rest.