Note: For a more in-depth look on Amaterasu, see Ōkami Wiki's article.
In Ōkami, the player controls Amaterasu in the form of a white wolf. While Amaterasu is referred to in the Japanese and European version of the game as a female, the North American version never states Amaterasu as a specific gender. Some characters, however, will refer to Amaterasu in either a feminine or masculine method, but neither are shown to be correct nor incorrect. While Amaterasu, when endowed with ink power, is seen by the player with red markings, cloud-like fur on her shoulders, and weapons on her back, most of the human characters in the game only see her as a plain white wolf; some believe Amaterasu to be the reincarnation of Shiranui (the white wolf that fought Orochi 100 years prior to the game's present), and do not recognize her spiritual nature.
If the player depletes their power by overuse of the celestial brush, Amaterasu will temporarily revert to this mundane white form. Issun, an arrogant, inch-tall "wandering artist" seeking out the 13 Celestial Brush techniques for himself, accompanies Amaterasu (whom he calls "Ammy" or "furball") and serves as a guide, dialogue proxy, and as comic relief. He grows in character along with Ammy throughout the game, eventually becoming her true friend, inspiration, and eventually her savior.
Amaterasu originally existed in the Celestial Plain, ruling over the Celestials and the mortal world as a protector deity. Alongside Waka, she battled Orochi, the eight-headed serpent who attacked and wreaked havoc upon the Celestial Plain. Waka told Amaterasu that Orochi could only be defeated by the Chosen One, a human named Nagi. Hearing this, she dragged Orochi down to the human world to wait for Nagi's birth. Meanwhile, Waka and the remaining Celestials fled into the Ark of Yamato, where all except Waka perished to an ambush of demons led by Yami, the ruler of darkness.
With each passing year, Orochi dined on another maiden from Kamiki Village on the annual festival. Before every festival, Amaterasu appeared around the village in the form of a white wolf. The villagers assumed her to be Orochi's familiar, naming her Shiranui. Eventually, Nagi fought Orochi, and through his combined efforts with Shiranui, he was able to seal Orochi away. Shiranui, however, died from poisoned wounds inflicted during the battle. Taken back to the village, she was hailed as a hero, and a statue was built in her honor. However, after her death, her Celestial Brush powers had scattered, leaving her drastically weakened, with only her original ability, Sunrise. Furthermore, the peoples' faith in the gods had dwindled, leaving her even weaker.
The main story of the game begins one hundred years after Shiranui's death. When Nagi's descendant, Susano, removes the sword Tsukuyomi that had sealed Orochi away, Orochi wastes no time in taking over Nippon once again. Sakuya, the wood sprite, revived Amaterasu within the statue of Shiranui, giving her the Reflector Divine Retribution. Together with Issun, a loudmouth Poncle found within Sakuya's robe, Amaterasu sets off to revive the Guardian Saplings scattered across Nippon and restore the lands to their original beauty and remove evil's hold. Throughout her journey, Amaterasu is reunited with many of her powers, and regains people's faith in the form of Praise.
Eventually, Amaterasu, with the help of Susano, manages to destroy Orochi. She then continues her journey through Nippon, regaining more of her brush techniques, and further restoring people's faith and the lands. Finally, she finds herself in Kamui at the Ark of Yamato. Boarding it with Waka, she finds herself fighting previously defeated bosses, including Orochi. Then, she finally faces off against her archenemy, Yami. With the aid of all the people she met in the form of prayers, her power is fully restored and she is able to vanquish him. She and Waka then return to the Celestial Plain to restore it, and finally bring peace and harmony back to the world.
Divine Instruments are heavenly weapons Amaterasu uses in battle. They appear floating on her back and can only be used during battle. There are three kinds of Divine Instruments: Reflectors, Rosaries and Glaives.
One of the Chihuahuas in the Chihuahua race featured in the game God Hand is named after Amaterasu.