The screams constantly buzzed in Layla's mind when she used the power of the Celestial Black Sword. She didn't know what and whose screams they were, nor if everyone who used the sword experienced the same thing, or was it because she was a Hannya and was more in tune with others' emotions?
Either way, she did know that it wasn't just the screaming. With each scream, it was almost as if she was experiencing that person's pain, what they had gone through. All those sentiments were rushing to her head, whether physical or emotional.
It was enough to make some people go mad, even if they had experienced this type of thing for a short while, but Layla was strong. She needed to constantly control her emotions to use the sword's powers and her True Hannya form.
After all, the negative emotions were what powered her, which was why she believed that this sword was the perfect partner meant for her. The more pain she handled, the stronger she would get.