Miko

In Shinto, a miko (巫女) is a shrine (jinja) maiden or a supplementary priestess. Throughout the Sengoku jidai of Japan, miko were human priestesses who often used their spiritual powers to combat evil spirits, demons, and ghosts in order to protect those who were defenseless against supernatural threats. In modern Japanese culture, the shrine priestess' has apparently been an institutionalized role in daily shrine life, and they're trained to perform certain ceremonial tasks, ranging from sacred cleansing to performing the sacred dances.

History
Miko are the shrine maidens of Japan beginning in the Sengoku jidai of Japan. In ancient times, women who went into trances and conveyed the words of a god were called miko, not unlike the Oracle at Delphi of Ancient Greece.

Characteristics
Priestesses are human women who are trained as healers and warriors. They mainly combat demonic threats, and are thus normally well versed in the occult and demonology. Miko are generally skilled in some variety of martial art or the use of a traditional Japanese weapon (e.g. yumi (longbow), tantō (knife), or any of the various Japanese swords: katana, wakizashi, etc.). True miko are also attributed with spiritual powers that could be utilized to erect barriers and perform "magic," especially o-fuda. Thus the level and power of a priestess is determined by the strength of their spiritual powers. However, while one with high-levels of spiritual power could pursue the role of a priestess, this does not guarantee that all priestess have legitimate supernatural powers or above average spiritual power.

The traditional costume or dress of a miko is a chihaya, which consists of a scarlet red hakama (divided skirt), a white haori, and tabi.

Dark Priestess
Kuro Miko (黒巫女; Japanese for Black Priestess) are sort of an evil counterpart to traditional miko. Dark priestesses often serve as a renegade priest or evil sorcerer. Like benevolent miko, they are trained in similar spiritual arts and may have an intimate weapons knowledge. The kuro miko is often well versed in demonology and has a strong command of black magic.

While kuro miko also wear chihaya, the colors tend to be darker (two often used color schemes are black and purple, or black and gold). In some anime series, kuro miko wear masks while performing clerical duties, both for effect and to hide their identity.

The priestess Tsubaki is the only notable example of a kuro miko or dark priestess. In fact Tsubaki demonstrates virtually all of the attributes of a kuro miko both in her control and summoning of demons as well as her affinity for dark colored clothing.

Notable miko in InuYasha

 * Midoriko †
 * Kikyō †
 * Kagome Higurashi
 * Tsubaki † (alive in manga)
 * Momiji
 * Botan
 * Hitomiko †
 * Kaede
 * Tsukiyomi †
 * Kanade †
 * Kikyō clone †

Trivia

 * It is somewhat difficult to assign a strict definition or English equivalent translation to the Japanese word "Miko," though the terms Prophet, Medium (as in Oracle), Shrine Maiden, Priestess, Nun, or Sorceress are often used.
 * In some romantic stories and bishōjo comedies, mikos are sometimes portrayed as attractive but overly serious and temperamental girls who are incapable of dealing with boys (such as fearing or outright hating them).
 * Supposedly miko were virgins, though it is unlikely that this was true. It is probably true that when a woman who was serving as a miko married she abandoned her duties at the temple in order to be with her husband and new family.
 * It should be noted that kuro miko do not exist in real-world Shinto.

Miko Sacerdotisas Pendeta wanita 巫女