Bar studied the waste from a distance, the edge where the peasants tried to burn back the purple vegetation blurred and indistinct. Magenta crept over the black, an almost visible advance.
There are a bunch of contradictions in the first few paragraphs, so I'm going to sound mean and snarky here. You say it's a waste, but then you say there's all this vegetation. A jungle, in fact. To me, a waste is more like a desert, so throughout this I was having to remind myself that you meant a jungle. Then you use two colors as nouns, and I don't know what you're referring to. The vegetation's purple, so it's not that... magenta light? magenta water? Is magenta a thing? And what's black?
A distance away a peasant team worked, silent and grim, the only sound the axes and saws cutting a swath through the vegetation. He wasn’t sure of the reason, although he could guess. They worked in teams, one team resting while the other cleared a space deeper into the alien jungle.
You told us Bar is at a distance. Yards? Miles? Paint some more picture for me -- the landscape, the time of day, the people... Also, you said they were burning back the vegetation, and now you say they're cutting it down.
They wouldn’t go to all this work to push the waste back—they had that process well rehearsed, as ineffective as it might be. There must be someone trapped behind the edge. They'd penetrated perhaps eighty meters into the edge, an odd shaped bulge into the wasteland border.
The first team kept their weapons ready, eyes never stopping.
They're not actually resting, then.
As quickly as the vegetation was cleared, a third team dragged it away to toss it on the smoldering pile. It burned sluggishly.
OK, but when you say they're "burning back the purple vegetation" I'm picturing the controlled burns they do in parks...
One of Bar’s sisters had a lemon tree in her garden, perhaps the last one in the human lands, and this smell was enough like the scent of lemon to call up the comparison. Few of these ever would have smelled that, let alone tasted the acrid fruit.
He's far away, yet he can smell... the smoke?
A shout went up and the teams surged forward, guiding a handful of exhausted farmers from the waste edge.
These are two complex actions -- surging forward, and guiding out survivors. Be more specific.
The wasteland had grown to encompass another farm, the people trapped behind the line. A straggle of cows and sheep, accompanied by dogs, burst from the purple boundary and spread out into the green human lands.
If the jungle grows fast enough to trap people, wouldn't it be creeping as we speak? And yet you said earlier that people don't bother to fight it unless someone's trapped? If getting trapped is dangerous enough to require rescuing, how does anyone sleep at night with this stuff crawling around?
Bar heard a shout behind him, and the ratchet of a crossbow as his patrol team came up behind him along the ledge.
The farmers heard the shout, but knew enough to go on alert toward the wasteland edge rather than away.
Be more specific about what the farmers do.
Bar ran, his patrol behind him. Whatever was about to happen he would be too late to either stop it or help. The crossbow was a short-range weapon, but deadly within its limits.
So why is he running? Also: what do they have with a longer range than a crossbow, if that's considered short-range? Why aren't they carrying that instead?
Along the edge where purple and green mixed the peasants drew back in a staggered line, bows coming up, swords and knives ready.
Every time Bar saw the wasteland creatures there was something new. The first emerged from the back of the area where human saws had encroached on the alien wasteland, more than twice as tall as any man. Its nose was broad and flat, its body visibly that of a browser attracted by the scent of the cut vegetation.
You need to be more specific in describing the critter. Just for amusement, I'm going to assume it's a moose.
Bar winced. He would need to make sure the peasant councils were reminded to burn the edge as they cut. Just because it was a browser did not make it any less dangerous. If hungry enough, it would come out into the human lands for the cut stems and branches.
That doesn't sound dangerous.
Behind it others appeared, some obviously predatory but ignoring the herbivores around them. They crowded shoulder to shoulder and stared out into the open human lands as if surprised to find space there.
What does "obviously predatory" mean?
The humans held their fire, backing away one careful step at a time.
Keeper Bar and his ten slowed, moved cautiously into a position where they could support as they got closer.
So your statement that they wouldn't arrive in time was wrong.
A wasteland creature near the back of the pack reared up onto its hind legs with a roar, leaving the visibly unarmored underbelly vulnerable, and one of the peasants took the shot.
The thing screamed as the arrow sank in, and Bar shook his head. Only the eyes were vulnerable.
If the arrow sank in, then obviously the underbelly is vulnerable. What did you really mean?
Its scream became a howl of rage, and it spat the arrow back at the humans much faster than it had emerged from the bow. One of the humans fell, but because the bolt hadn’t been shot from a bow it hit him flat, across the head. He fell back.
So, these critters aren't dangerous unless you attack them... so why should I worry about these idiots getting hurt? They deserve it for provoking them.
Neat trick, taking in an arrow from your belly and spitting it out your mouth. You should describe that more.
The wasteland force surged forward, jostling each other, tusks, hooves, claws and teeth visible even on forms which held no other similarity to anything in the human lands. Too many to kill, and if the peasants killed one it would only start a feeding frenzy. The Keepers had learned that long ago.
A feeding frenzy of herbivores doesn't sound all that dangerous. Also, you refer to them as animals -- but they sure aren't acting like animals.
“Fall back!” Bar shouted, and strode forward. “Fall back!”
The humans heard it. A few began to retreat as ordered, pulling others with them until they clearly stood on the human side of the charred and denuded wasteland edge.
The animals slowed as they approached that edge, which Bar had not expected. One snorted and shook its heavy head, backing away as if trying to get away from some unbearable stench. Others skittered sideways, crowding toward one side of the open space, away from something Bar could not see.
Bar’s people moved up in support—not too close. It took Bar a moment to see the one human shape which remained at the edge, but it didn’t attempt to move out into the human lands. It took a single step into the sunlight and raised a hand, not toward the humans but toward the animals massed at the edge.
If it's human, give it a gender.
The animals backed away, some now staring longingly toward the purple jungle.
Why don't they leave?
A woman alone, she stood between the enraged animals and seemed to push them back as she walked forward, one careful step at a time until they broke and ran, back into the magenta forest.
Magenta, not purple? Another contradiction.
Only then did she turn to face the humans, who stirred uneasily and surged toward the stranger.
“Shaper!” someone screamed, and with a howl of rage the humans went after her.
When Bar looked again, she had vanished.
Why did he look away? Wouldn't he keep a close eye on someone acting strangely?
Is the world-building strong enough: well, I don't have a clear enough picture of what's going on to answer that. Not the sequence of events -- I mean the context: why these things are happening, why they're important, why the things these people do are reasonable and logical. Plus, you frequently contradict yourself in the details. Therefore, I'm not sure what you know, or don't know, about your world.
Would I keep reading? No.