She had been unable to see it before, but she could now even use the faint lingering regrets of the deceased. She could reconstruct the powers of those who had died in this place and use them for herself. More than a million souls.

...

“Die.” But her opponent was faster. Before the apparition could make its move, Romiko dropped like dead weight. Her monster quickly dissipated, leaving no trace of its existence behind. She must have been planning to kill Yogiri just to show off her new powers, but he had beaten her to it.

-Volume 4 pages 152 and 154