Shichishitō

The sapient blade, Shichishitō (七支刀, literally Seven-Branched Sword), was passed down from the Shodai Oyabun to the present day. A blade forged from pure condensed natural energy. It can only be wielded by a sage as its touch brings death to those who've not become one with nature.

Only its main branch of massively compacted natural energy remains visible to non sages. The six side branches cannot be detected by others. The blade's edges span the width of a single atom. Shodai Oyabun is said to have cleaved through Susanoo to slay its summoner during the Ten Fingers of Bloodstained Hands, leading the remainder of his people to safety.