Sacred Arrow

are ordinary arrows that are imbued with varied levels of the innate spiritual strength and abilities of a priestess or priest/monk. Such a tactic is utilized by someone with middle-level or even uppermost-level spiritual powers.

Although sacred arrows are not always considered a very accurate attack, they can be very effective or even quite deadly coming from the hands of an experienced archer.

History
The Yumi-&-Ya, the Japanese longbow and arrow, became a weapon against evil, according to a Japanese legend; at that time, the Imperial Palace was taken over by an evil demon, which caused the Emperor to fall ill with great anxiety and suffering. When the Imperial High Priests tried and failed in their efforts to destroy the demon and dispel the Imperial household of its influence, they were at a loss. Finally, an archer, Yorimasu Minamoto, was summoned to the Imperial Palace in the hopes of slaying the demon with his bow and arrow, ridding the palace of this plague. With a steady hand and a virtuous heart, Yorimasu Minamoto vanquished the demon with the first arrow, and his bow was declared to be a Hama Yumi, an "Evil-Destroying Bow" (and the first arrow, a Hama Ya, an "Evil-Destroying Arrow").

While the founder of this spiritual technique in the series is unknown, the Miko, Kikyō, is the earliest known user of sacred arrows seen. According to InuYasha, Kikyō, was a master archer. Her skills as a priestess and great spiritual power earned her renown, and her usage of sacred arrows were trademarked as well. Slaying numerous troublesome demons with her sacred arrows, Kikyō would go on to teach her younger sister Kaede the proper use of sacred arrows too.

After Kikyō became the guardian of the Sacred Jewel, she eventually sealed away a minor yōkai called Ne no Kubi. Before her premature demise, Kikyō used the last vestiges of her strength to bound the half-demon Inuyasha to a tree with a sacred arrow. Fifty years later, Kikyō's reincarnation, Kagome Higurashi, broke this seal and became gradually exceptionally proficient in the use of sacred arrows herself over the months.

Capabilities and Effects
Sacred arrows, when charged with spiritual power, can have a devastating effect and pulverize even demons. Depending on the archer's spiritual power, the arrow's power becomes such that it can destroy buildings in a combustible manner. Sacred arrows can also blessed/anointed prior to being charged with spiritual power, intensifying their effects. They can even be made to be fine-tuned against a specific opponent, as seen when Kikyō used soil from the cave where Onigumo became Naraku on her arrows, making them effective against him; although Naraku became powerful enough to be unaffected, his incarnations were still vulnerable.

Certain master archers, namely Kikyō, can control the extent of their spiritual power at will and seal enemies in perpetual sleep with their sacred arrows instead of exterminating them. Such arrows are referred to as the "arrow of sealing," and are used for demons who are otherwise invincible. Only when the one who sealed the demon wishes for said demon, or half-demon, to be revived will the strong spell of perpetual sleep/suspended animation be lifted.

Furthermore, exorcism arrows can be used beyond the simple expedient of exterminating or sealing a demon; they can be also be used for other tasks such purification or breaking barriers. Moroha has the ability to shoot a sacred arrow in the air, which then creates a barrage of several sacred arrows that rain downward on her enemy. She calls this specialized technique "Heavenly Arrow Barrage."

In the second season's premiere of Yasahime: Princess Half-Demon, Moroha had fired about three sacred arrows to fend off and wipe out an ever-expanding horde of mindless demons to buy Towa more time. Now that she no longer carries the red Rainbow Pearl, which was merely preventing her innate spiritual powers from achieving their true potential, just one arrow alone could unleash a much larger and wider burst of spiritual energy that can encase a multitude of victims while eradicating or purifying them into nothingness. Such an effective and powerful feat from Moroha had not possible throughout the first season, due to the Red Pearl's demonic interference.

Trivia

 * Naraku has referred to these arrows as an "enchanted arrow."
 * The greater the archer's spiritual power or the more spiritual power imbued within the arrow, the greater the aura of energy surrounding said sacred arrow.
 * In the anime, sacred arrows were often surrounded by pinkish-purple auras, whereas in the movies this aura was colored blue.
 * While it is hinted at in Kagura's Dance and Kanna's Mirror that arrow shafts intended for use as exorcism arrows are made from the fallen branches of spiritual trees such as the Goshinboku, there are several indications that this is untrue. Most notably, the supply of which would not necessarily meet with the demands seen throughout the series; this is seen in the times that Kagome and Kikyō were both able to use ordinary arrows laying around and channeled their spiritual power through them to great effect.
 * In the manga version, upon Kikyō's resurrection, Inuyasha is able to cut Kikyō's sacred arrow in half, while keeping the Tessaiga in the transformed state. Instead, in the anime version, Tetsusaiga's transformation is disabled, with Inuyasha being hit by it.
 * Moroha's mentor had scornfully mocked her teenage pupil's spiritual level and prowess, stating that it was too weak for the arrows to be called "sacred."