This is a really solid start for a WebNovel chapter. You have a great sense of grit here, and the world-building details—like the "outskirt rats" and the unfair 70% cut—immediately tell us what kind of brutal environment Graves is surviving in.
For WebNovels, pacing, readability, and impact are everything. To make this punchier, we can fix the typos, tighten the dialogue punctuation, and enhance the imagery so the reader really feels the tension.
Here is the line-edited version, followed by a breakdown of the specific changes made.
Revised Version
Graves's arm grew tired. They had been beating the devil for a while now, and the bastard just refused to die, though it had grown visibly weak from its accumulated injuries.
"That's enough," a husky voice cut through the air from the back. Everyone turned toward the sound, though they didn't need to look to know who it was.
Harry Benjamin had been their leader since Graves joined the small gang. Well, it wasn't like they had a choice—he was bigger than all of them, so no one dared challenge him. He called himself "Terminator," a name everyone obediently used. Stepping forward, he pulled out a handgun. Graves and the rest stepped back, watching him closely. It was always a wonder to Graves, seeing someone end the life of a devil by just squeezing a trigger.
"Hey, canine devil," Harry said, addressing the beast.
Sighs rippled through the small gang. Someone whispered, "He always does this."
"I want you to know that I have no grudge against you, just as you shouldn't have against me," Harry continued, gesturing to himself and the gang behind him. "We're just trying to survive."
Still pointing the gun at the dangling devil trapped in the net, he pulled the trigger.
BANG!
The shot rang out, almost deafening Graves. He grimaced, clamping his palms over his ears while the other kids had their own sharp reactions. Blood and brain matter splattered everywhere.
"Cut out the crystal core and bring it to me," Harry ordered.
The crystal core was the main objective for outskirt rats like them, the only reason they risked their lives to kill a devil—not that their lives weren't already meaningless. The meat had some value too, but it wouldn't sell for nearly as much as the core. Most of the time, they divided the meat among themselves, leaving whoever wanted to sell their portion to do so. The money made from the crystal core, however, was shared unfairly by Harry, who pocketed a greedy seventy percent of the gains.
"Greedy bastard," Hope cursed quietly, glancing at Harry's back.
A few kids stepped forward to handle the task of extracting the crystal core from the devil. In no time, they were through. The meat was divided, and Graves walked away with half a kilogram.
"Kids who can't hunt would die to have this," Graves muttered to himself, trying to find value in his unfair share.