The Tsuzurao met by Amaterasu is actually the demon lord Ninetails in disguise. The real Tsuzurao was killed and her identity stolen in order to trick Amaterasu into retrieving the Fox Rods and to infiltrate Queen Himiko's palace). The fake has red beads and hair_over_one_eye, while the original has blue beads.
Judging from her full name in the story, δΉεδΉε°Ύζ―δΈε°Ό (Tsuzurao-no-Bikuni), she is modeled after the legend of Yao Bikuni.