Board Thread:Naruto Discussions/@comment-24593592-20140716142357/@comment-28861328-20140716155638

Kaguya is based on the myth of "The Tale of the Bamboo Cutter". Specifically Princess Kaguya from the myth. The horns on Kaguya? She was known as the "Rabbit Goddess" in the real life myth due to rabbit ear-like appendages growing out of her head. She's really the moon, more specifically Tsuki no Miyako - the Capital of the Moon.

There is little connection between Kaguya and the Six Realms myth.