Sari, the daughter of Kosa, the current leader of the sasakori.
When the time comes, she will take over his role and be the new leader of the sasakori.

It is tradition that the first offspring of the leader becomes the successor and therefor new leader of the sasakori. They do not care if the offspring is male or female as gender discrimination is a concept that doesn't exist for them.
The offspring of the current leader is given a horn piece (here pictured on the necklace) that belonged to the first sasakori leader and is passed down from generation to generation as a talisman and symbol of leadership.
It is also tradition that the names of leaders and their offspring consists of syllables from the name sasakori.

Sari, Sasakori & Art are mine