Shinto Legend on the Creation of the World
At the beginning of the World, there is one Being by the name of
Izanagi. After a visit to the Netherworlds, he used water to purify his eyes, and thus, from the left eye, created
Amaterasu, while from his right eye, created Tsuki-Yomi. Amaterasu was the Sun Goddess and Tsuki-Yomi the Moon Goddess. Finally,
Susanowo the Storm God, was born from Izanagi's nose.
Amaterasu and Susanowo argued and fought each other for supreme power. Susanowo finally went on a killing rampage to prove his strength and Amaterasu hid in a cave in heaven.
Similarities between the Legend and Uchiha Itachi
Susanowo - Itachi, like Susanowo, went on a rampage to prove his strength, although Susanowo did not went to the extent of wiping out his entire family.
Tsuki-Yomi - The Moon Goddess. Itachi's technique to brings the victim into a time warp zone where there is always a bloody red moon. Legends also has it that the Tsuki-Yomi killed
Uke-Mochi, the Goddess of Food (Amaterasu's close friend) after she offended the Moon Goddess, making Amaterasu so angry she vowed to never see Tsuki-Yomi again (explaining why there are days and nights). Tsuki-Yomi's act of violence could also be the inspiration for the red moon in Itachi's technique.
Amaterasu - The Sun Goddess. Itachi's black fire technique to burn through barriers, also known as Great Shining Heaven.