Kusanagi was enslaved as a young child by Yamata no Orochi who killed his parents, Priests of a Shinto Shrine. Yamata no Orochi made Kusanagi an Aragami by giving him seven metamas, then charged Kusanagi with protecting Kaede the Kushinada. But he rebelled when he thought they killed Kaede. Early after Kaede disappeared, Kusanagi discovered that if he killed Momiji, the Aragami would die as well, giving him revenge over Kaede's death. Thankfully, the TAC stopped him before he could kill Momiji. After that, Kusanagi takes on the duty of protecting both Kushinadas, even though Kaede hasn't been found yet. Later in the series, Momiji Grows an affection for Kusanagi,but he's too thick headed to realize it. When Kusanagi finally realizes Momiji's feelings for him, he starts to reallize that he has feelings for her too.