Hokuto

Having neither nature or attachment, she reigns rule over the shichisei as the strongest shikabane. Spoiler It was later known that the shichiseis wanted to activate hokuto's powers without any sacrifice so got Makina to teach Hokuto's role: Makina's enemy. In the process, it is revealed that Hokuto was once a human sacrifice not knowing anything of the world thus her way of understanding things is to destroy it. She was born to be killed thus there was no reason for her death nor her revival making her the most powerful and deadliest tool among the antagonists. She eventually became the betrayer monk's shikabane hime after destroying the being providing en for all the shikabane hime. Desperate and depressed of his former shikabane's death and the organizations' deception towards the monks, they work towards destroying shikabane.