Priest

Priests, priestesses, and holy people of various kinds inspired by real world counterparts from Japan's warring states period are found throughout the InuYasha series.

Shintō

 * Priests: Shintō Priests are often shrine keepers and may possess the same, or greater spiritual powers as Miko do. Many Miko seem to be under the tutelage of Shintō Priests. It is difficult to ascertain the powers of Shintō Priests in InuYasha, as many have not been seen, but one in the modern era is Grandpa Higurashi.
 * Miko: Miko, or priestesses, are shrine maidens who guide people with their spiritual powers and aid Shintō Priests in their duties. Many Miko are seen in InuYasha, such as Kikyō, Kagome, Kaede, Midoriko, Tsukiyomi and Hitomiko.

Buddhist

 * Wandering Monks: Wondering Monks go around on pilgrimage, traveling the country to exterminate demons and aid people through spiritual guidance. Miroku is an example of a wandering monk.
 * Temple Monks: Temple Monks are Buddhist priests who are keepers of a temple. Many are quite powerful, using sacred spells to ward of demons. Master Mushin is a temple monk who raised Miroku.
 * Warrior Monks: The Warrior Monks of Japan were Buddhist Monks who did not follow the teachings of "causing no harm to sentient beings". They often sold their services to the highest bidder or fought on the side of their own choosing to further their cause and maintain their hold on properties and valuables that had been "donated" to them. They appear specifically as the white-hooded fighters carrying Naginata (halberds), defending Izu-Toyas castle in the third InuYasha movie "Swords of an Honorable Ruler".

History: Those warrior-monks were a major problem for every warlord ruler of Japan since approximately 700 AD. A great number of them were exterminated when they got involved in the war between the Taira and Minamoto clans in 1180's. In 1580 Oda Nobunaga nearly wiped them out, but Toyotomi Hideyoshi was still troubled, and Tokugawa Ieyasu was forced to deal with the remains of them in 1615.

Mountain Priests

 * Yamabushi: Also known as Sages, they use their spiritual powers in tandem with nature. In InuYasha, Tōkajin and his Master are shown to be sages (though the former gained his powers through a demon tree).

History: While Pre-Edo Japan lumped the Mountain Priests into the same category as Shinto most agree that they are a different breed. The Mountain priests will often accompany Shinto priests in specific ceremonies pertaining to the spirits of their area.

Powers of the Priesthood

 * Purification: Priests, priestesses and monks have the ability to remove demonic auras from people, places and objects.
 * Sutras: Written incantations that act as demon destroying amulets. Sutras are also used to identify demons who have hidden in human form as a single touch from a powerful sutra is capable of instantly revealing a disguised demon. Not only that but sutras may be used to erect physical spiritual barriers.
 * Barriers: Energy fields designed to trap or repel demons or any other unwanted beings. Powerful sages like Hakushin were able to form barriers that no one human or demon were able to pass through.
 * Shikigami: Spectral entities created and empowered by the creators spirit energies capable of assuming a variety of different forms. These spirit puppets also have the ability to gather and collect items (physical objects) and energy (souls) as seen when dark priestess Tsubaki sends her spirit puppet to collect drops of Kagome's blood or Kikyō's shikigami who gather souls to help sustain her body after she is revived by Urasue.
 * Sealing: When a priest or priestess encounters a demon that is too powerful to destroy outright the holy person will often employ a combination of enchantments and barriers to bind the demonic being into a kind of spiritual prison. The ogre found in the Forbidden Tower who is released by Tsubaki is an example of a demon being sealed behind a barrier of enchantments. Priestesses like Kikyō were capable of firing arrows of sealing which could bind demons to a sacred tree for eternity.
 * Armed Combat: Living in the feudal age, monks and mikos alike have found training in the more mundane arts of battle vital to their survival. Kikyō and Kaede employed bows and arrows with great efficiency and accuracy. Priestesses Midoriko and Tsukiyomi were seen wielding swords in combat against demons. Miroku used his traditional pilgrim's staff in battle, sharpening the end of the shakujō allowing it to double as spear. In addition holy men and women often channel their spiritual powers into their weapons allowing them to deal both energetic and physical damage.
 * Healing: In the course of their training to become monks or priestesses it is common for initiates to be taught in arts of medicine. Kikyō and Kaede had extensive knowledge of a variety of different plants and herbs that could be used to cure a number of sicknesses. Kikyō being a miko of extraordinary power was also said to have the ability to save those on the brink of death dispelling the pallbearers of the underworld with a single touch.
 * Miasma Resistance: Priestesses like Kikyō were shown to not to be as vulnerable to effects of demonic miasmas as ordinary humans. Miroku claimed in the episode "Kikyō and Inuyasha, Into the Miasma" that his training as a monk allowed him to withstand the poisoning effects of a dense and formidable miasma cloud.
 * Curse Magic: Demonstrated by the dark priestess Tsubaki when she attempted to force Kagome to slay Inuyasha a dark miko can kill or control another being from a distance.
 * Spiritual Awareness: In combination with their other abilities sages seem to have an abnormal "sixth sense" that enables them to detect both barriers and demons alike even when a nefarious being is concealed by magic. Kagome possessing Kikyō's reincarnated soul has the unique gift for seeing the shards of the sacred Shikon jewel. Kikyō herself was able to detect Naraku's aura even after he had disguised himself as a feudal lord.
 * Creation and Empowerment of Mystic Objects: In addition to channeling their spiritual energy into their weapons as Kikyō did with her bow sages with tremendous amounts of supernatural power are able to craft objects of mystic power like the Sacred Jewel. Midoriko, the jewel's creator, used the fabric of her own soul to capture and seal a demonic spirit inside of her own body before expelling it along with her soul forming the Shikon Jewel. Such objects differ from items that might act merely as conduits (Kikyō's bow, Miroku's staff) in that the object itself becomes a source of magic independent of its creator. The cauldron designed by Lady Kanade which helped to protect Hōraijima is another example of a mystic object created by a priestess.