Who is the five-star stone of the ancient scroll given to?

Give it to Arazu and he will tell you how to fix it.

The ancient scroll 5, the Star of Azula, will give the priestess a white star (plus a good priestess attendant), which can absorb animal souls, equivalent to a reusable small and medium-sized soul stone, and give a black star to Neilaka, equivalent to a reusable black souls stone.

In fact, no matter the white star and black star can only hold one soul at a time, it is basically useless, far less than the ordinary soul stone.