Mikoto Kusanagi is a female member of the Kusanagi Clan, one of Orochi's two sisters, Mistelteinn's first known contractor, and Takeru and Kiseki's ancestor. She along with her unnamed sister shared the Hyakki Yakou curse.
Mikoto's appearance is not strictly described aside from Lapis' current form being based off of her appearance.
Mikoto was one of the older twin sisters of Orochi Kusanagi who shared the burden of the Kusanagi Clan's Hyakki Yakou curse that plagued each generation of daughters born into the family. When Orochi left home to aid the Magic Side during the First Witch Hunt War, Mikoto was mysteriously taken in by the Inquisition and contracted to Mistelteinn to combat her brother's Lævateinn. Mikoto forcibly entered God Hunter mode and Orochi was forced to slay her in his own God Hunter form, which resulted in his age-long depression.
Orochi's sole motivation that inspired him to rejoin Valhalla and contract with Mother Goose was to accomplish the latter's plan in replacing Sougetsu Ootori upon the seat of Godhood and bring about an "illusory world" where he would have Mikoto back.
When Orochi lost his duel against Takeru, the former began to see a glimpse of Mikoto welcoming him back into her arms.
Hyakki Yakou: While her affliction to the family curse was minimal compared to her older twin sister, Mikoto still carried the demonic burden her entire life. The severity however is unknown.
Sacred Treasure- Mistelteinn: Forced to contract with it during her capture by the Inquisition, Mikoto was apparently properly suited to wield the legendary weapon and activate God Hunter form.