Amaterasu looks like an ordinary white wolf to any normal human that lays eyes on her. However, her true form shows her covered in red and black markings and having a "divine instrument" on her back. Some humans can see her true form, but the reason for this is unknown. The reason she is a wolf is due to her being based off of Japanese legends; one of which holds 13 different animals, 1 for each month (and an extra interchangeable one). The animals are: wolf, dragon, mouse, monkey, rabbit, chicken, tiger, horse, bull, boar, cat, snake and sheep.
100 years before the game (sort of...) Amaterasu was known as Shiranui, a white wolf who supposedly worked for Orochi, an 8-headed dragon that terrorized the land. Every year, Orochi would choose a woman from Kamiki village to eat as a sacrifice to him, and Shiranui would collect the maiden. However, Shiranui was actually just waiting for someone brave enough to fight and defeat Orochi. This man turned out to be Nagi, who took the sacrifice's place one year so he could take down Orochi. (This later turned out to be only half true.) Nagi was unable to win, however, and just as Orochi was about to lay the finishing blow, Shiranui showed up and fought Orochi while Nagi regained his health. After a long battle, both beasts were worn out and near death, and Shiranui howled to the heavens, parting the clouds and showing the moon. Nagi, who was now healthy, raised his sword, which absorbed the divine light. He then defeated Orochi and sealed him away. Shiranui was taken to Kamiki village and buried in a statue.
100 years later, a shady character went to Orochi's former stronghold, the moon cave, and took Nagi's sword. This awakened Orochi, and the character ran away in fear. Orochi then put a curse on the land, and only Kamiki village was saved. Sakuya, a wood sprite, sealed the village away from the spreading curse and awakened Shiranui. However, he was now stripped of his old powers and form, and was now known as Amaterasu, goddes of the sun.
Amaterasu first wanted to sleep, but was prompted to purge the land from darkness when a small man appeared. He called himself "Issun, the traveling artist." He decides to go with Amaterasu on her journey to gather her powers and purge the land of darkness, but Issun merely wants to go to get Ammy's powers. The two travel across the lands, regaining powers and defeating demons. The two grow suprisingly close despite their first meeting, but throught the entire adventure, Issun never paints one painting.
The two meet many people on their adventure and fight many battles; however, the most noteable person they met was Waka. He appeared many times, constantly giving them strange prophecies of the future. He also was the first to mention the fact that Issun had not painted a thing. After Amaterasu defeated Orochi alongside Susano, the man who accidentaly freed him at the begginning, Amaterasu and Issun continued on their adventure and defeated more powerful demons, but they eventually left that land and entered another.
They headed north into the land of Kamui, Issun's home. Here, the land is freezing and the twin demons are trying to make it an icy tomb. Amaterasu soon meets Oki, a warrior who wishes to defeat the demons. However, he is obsessed with defeating them, and he cares for nothing else. Amaterasu leaves him and finds out there is a girl named Lika who can recite a prayer and heat Kamui. On the way to find her, they come across a village called poctan, which is filled with Issun's kind. The village elder, Isshaku, reveals the poncles perpose: to inspire humans to believe in the gods. He also states he was training the people in the village to do just that... but he trained them strangely strict. He trained his grandson expecially hard, but he got fed up and left. They follow her through a door that leads to Kamiki Village... 100 years in the past.
Here, they meet Nagi, who turns out to be a bit of a coward. He mistakes Amaterasu for Shiranui and attacks, but after the fight he is knocked out. He isn't awake to see Orochi choose his sacrifice, so Amaterasu has to take him to the moon cave in place of the sacrifice, even when he is knocked out. Eventually, they find Orochi, who has Lika. Nagi woke up and helped them defeat Orochi, but it is nothing like the legend tells. Shiranui then appears and saves Nagi from one final attack, and is buried in Kamiki. Amaterasu then goes back to the present with Lika and defeats the twin demons alongside Oki. In doing so, she gains her final power.
After the battle, the Ark of Yamato, an object from earlier in the game, rises from the frozen lake it is buried in. Amaterasu chooses to board, knowing the source of her problems lies within. Issun, however, leaves, now that he has all of her powers. Waka appears and tells Issun to take responsibility and make believers, just like his grandfather, Isshaku, wanted him to. Amaterasu is then sealed inside the ark, where her origins are truly revealed: she was god of all things in the celestial plain, but the moon tribe sent an ark to the plain containing Orochi and Yami, the sopposed emperor of eternal darkness. The two consumed the celestials and destroyed the plain, leaving Amaterasu and Waka, the one who unknowingly brought them to the plain, on the mortal world. Amaterasu then goes to fight Yami, who strips her of her powers and kills Waka.
After slowly beating down Yami and gaining her powers back (except for sunrise, her signature move), Amaterasu is about to do one final vicory howl; however, Yami is still alive. He attacks Amaterasu and takes her powers again, assuming his true form: a giant hand, based off of mankind's desire to use their hands for evil. Amaterasu is left for dead, but she begins to hear the voices of the people she has met on her journey praying to her. Issun then shows he has finally accepted his meaning and is traveling as her missionary, asking everyone to pray for her. Amaterasu absorbs the peoples prayers and becoms Shiranui again. She destroys Yami and reunites with Waka (who survived the attack from Yami) and heads to the celestial plain.
Amaterasu is shown to be loyal like a wolf, yet sometimes playful like a household dog. She also can be either lazy (which is shown right off the bat, after she is revived by Sakuya) or very aggressive. She obviously can't talk, but many people seem to know what she is saying and treat her like an actual person. She also is shown to be a bit sarcastic at times, like when she lies down and sleeps while Waka tells her the story of Orochi's revival, which she already knows.
- There has been some conflict over how to pronounce Amaterasu's name. Some people think the "u" is silent.
- Some people also think Amaterasu is male, due to her showing affection for some of the female characters.
- Amaterasu, like most of the game, is based off of Japanese mythology.
- In the European and Japanese versions of Okami, Amaterasu is a female, but only in the American version is Amaterasu gender-less.
- Amaterasu's full name is Okami Amaterasu.