Parasitism

Benjamin had already seen things fairly clearly. These ghosts might once have been humans, animals... After death, their spiritual power had been shaped by the specific environment here, eventually forming these unusual yet stable spirit-body creatures.

Most of the time, they merely acted according to instinct. Perhaps they retained fragments of their personalities from life, but that was all.

As Benjamin controlled the little ice sphere to continue rising and then thawed it once more, the little bird fell into the illusion again. The dozen or so ghosts immediately recovered their wits and, with barely any hesitation, pounced on the bird once more.

In the process, they gradually moved beyond the ghosts' main range of activity.

Thus, water vapor carried the bird ever upward, while the soundproof ice sphere appeared and vanished, and the bird drifted in and out of hallucinations. Under Benjamin's guidance, those pitiful ghosts moved farther and farther from the bottom of the abyss.

Clearly, they were not very adaptable to unfamiliar surroundings. During the chase, ghosts would occasionally fall behind and turn back toward their home. In the end, only one particularly stubborn fellow remained, drawn to a place near the abyss's exit.

"They seem to be afraid of light." The System had been observing the ghosts as well, and said curiously, "Or rather... light elements? They're clearly nothing but pure spirit bodies, so why do they react to elements with fear? Maybe you should try light magic. You might be able to trap it."

Benjamin shook his head.

"Wouldn't that just kill it?"

At this moment, the surroundings were still extremely dark, with dark elements far denser than normal. Yet the final ghost that had chased them up was already beginning to struggle. Its body trembled in the faint light, and it had slowed considerably