Ame no Murakumo no Tsurugi

Ame-no-Murakumo-no-Tsurugi, also known as Kusanagi and the Heavenly Sword of Gathering Clouds, is a powerful Divine Sword from Japanese Mythology.

Summary
The Ame-no-Murakumo-no-Tsurugi is a Divine Sword forged by the Evil Dragon Yamata-no-Orochi and was sealed inside of his body as a means of protection. When it was slain by the Japanese god Susanoo, he retrieved it from the dragon's corpse and gifted it to his sister Amaterasu as a peace offering. It soon became one of three Imperial Regalia of Japan, all three symbolizing the Emperor, who was a descendant of Amaterasu, becoming a holy sword due to the blessing and faith of generations of Japanese people.

Yamato Takeru, the son of the 12th Emperor of Japan was granted Ame-no-Murakumo by his aunt, Yamato-hime, the woman responsible for creation the Ise Grand Shrine where it had been enshrined. He accumulated victories, until it was discovered it allows him to manipulate the weather, using the wind to blow away the flames and grass, which surrounded him earning the secondary name Kusanagi-no-Tsurugi.

He continued winning until his death caused by an illness having been cursed due to blaspheming one of Mount Ibuki's local gods and was returned. Afterward, Amaterasu gave the sword to a clan of Shinto priests and entrusted them with the duty of guarding over the Divine Sword. The clan then renamed themselves into the Kusanagi Clan and began to worship the sword itself as a minor god.

In the aftermath of the World War II, after the Empire of Japan had lost, the gods had given the divine sword to the Japanese Catholic Church so that the Abrahamic Heavens would taken the Japanese Pantheon under their wings in fear of retribution from other pantheons and factions, which Heaven accepted.

The Kusanagi Clan then converted into Christians and continued their duty guarding over the divine sword with the permission of Heavens. However, because of this decision, their alliance with the Five Principal Clans had turned strain.

In 2012, the Ame-no-Murakumo-no-Tsurugi was stolen by the Qlippoth Faction, presumbly around the same time as the Excalibur Controversy, and imbued the divine sword with a portion of the Yamata-no-Orochi's soul. The sword was later given by the faction to Masaomi Yaegaki, a former Exorcist of the Protestant Church, for his revenge. After Yaegaki was defeated, the sword was taken back to the Kusanagi Clan to be purified and resealed in their vault.

Appearance
The Ame-no-Murakumo-no-Tsurugi has the appearance of a tsurugi made out of gleaming onyx, decorated with glowing green Ancient Japanese symbols that dated from the times of the Kamiyonanayo. Connected to its handle is a long chain of jade magatamas, which act as a way to 'deactive' its divine aura.

However, this isn't its only form as it can transform itself into any type of sword the wielder feels most comfortable and experienced with.

Abilities
The Ame-no-Murakumo-no-Tsurugi is considered to be one of the most powerful swords from Japanese mythology, even considered to be the Japanese Excalibur. It possesses an immense amount of divine aura, to the point where one can mistake it for a true Holy Sword such as Durandal or Joyeuse. It can manifest a divine aura that is incredibly dangerous toward Devils and demonic creatures, to the point where a single slash of the divine sword is enough to kill a High-class Devil.

It possesses the unique power to manipulate powerful and deadly poisons, which is a power shared by its creator, the Venom Blood Dragon Yamata-no-Orochi. It can generate numerous types of deadly venoms, capable of affecting monsters, humans, and gods alike, though the poisons generated by it are most dangerous toward those of a demonic nature - the effects of its status as a divine sword.

It also possesses the power to generate and control weather - the result of the myth about it revolving around how it was claimed from the dragon's corpse by the Japanese storm god Susanoo, as well as how it has been worshipped as a minor guardian god for hundreds of year.

Formerly
After being modified by the Sephiroth Graal to have half the soul of the legendary dragon, Yamata-no-Orochi, sealed inside of the sword, it became a vessel to summon forth the Evil Dragon from the depths of the Japanese Underworld.

From the blade of the sword, the dragon's eight heads will sprout out to attack its enemies, either by having its heads bite the enemies or unleasing its poison-infused fire breath. The heads are capable of regenerating after being cut and also have access to the dragon's poisonous fangs which are imbued with a powerful poison feared by even the gods.

This ability was lost after the blade was broken and the spirit of the Yamata-no-Orochi was sent back into the depths of the underworld.

Trivia

 * Ame-no-Murakumo-no-Tsurugi's appearance is based on the Kusanagi-no-Tachi from "Fate/Grand Order".
 * Despite being considered a weapon, it is self-aware and is capable of acting on its own.
 * Due to the myth surrounding its origins, it can be considered a [ Dragon-Slaying] sword.
 * Yamata no Orochi being sealed inside Ame-no-Murkumo-no-Tsurugi is ironic as the sword was found from his corpse.