|As requested, here's my review/ I'm just going to be writing my thoughts as I come across them, so some of them might be invalidated later on. If that's the case, feel free to ignore them. :)
So, starting with your opening sentence, you have, "The scent of blood was in the air,..." This is a passive phrasing when you really want something active. Something like, "The scent of blood filled the air..." "filled" isn't the strongest verb but it's still probably better than a passive phrase. I personally like, "The scent of blood choked the air,..." "choked" is a violent, threatening word (which adds to the atmosphere of danger) while also starting off your story with a powerful action.
Beyond the passive wording those, this is a good opening sentence.
This is another passive phrase and one easily switched to active, " A woman was rushing through this dense forest,..." just exchange "was rushing" to "rushed."
Your whole opening paragraph is heavily passive. Whenever possible try to use active prose because it increases the impact of the words, making them more immediate and powerful.
This sentence is needlessly wordy, "The woman suddenly twisted her body, looking backwards." What you're saying here is that "she looked backwards." and "she looked backwards" conveys the exact same image as "the woman suddenly twisted her body, looking backwards."
As a quick tip helping verbs (any adjective that ends in LY) are generally considered weak. the reason for this is because there's almost always a single strong verb that conveys or that they're just unnecessary. Take this sentence for example. What modification does the suddenly add to the sentence? A sudden motion is a sharp or unexpected motion, but all movements are unexpected unless you foreshadow them in some way. Second, this is a high-stress scene, so any action would natively be sharp and forceful. What that means is that both modifications that "suddenly" added are already present in the scene just by virtue of its contents. This is the case for most helping verbs.
This next sentence in passive again, "The blade of a crude knife aimed for her head was swiftly deflected by a metal bracer on her arm." It also leads me to believe that the "suddenly" in the previous sentence was intended to connect her turning about with the knife coming at her. If that's the case, then I would suggest combing these two sentence (which is permissible because they are connected.) Something maybe like, "She twisted about, deflecting a spinning knife with the metal bracer on her left arm, and continued forward." (These are just suggestions and by no means intended as the perfect sentence. I endeavour only to show you the patterns and syntax of a more active sentence so you can develop your own solution. Take "continued." Continued is a good action, but it's not energetic. It's more a staying action. Something like "lunged" or "surged" might improve the sentence because they're words with definite, energetic and explosion actions."
Two things for this sentence, "..a platoon of monsters on the hunt." First, the opening of this sentence in passive. A quick solution would be, "A platoon of monsters crashed through the forest behind her." Second, I would consider exchanging "platoon" for a different word. Platoon is a military term referring a group of soldiers which gives the impression that these monsters are a literal platoon of soldiers. This might be what you intended, though, due to them throwing knives.
The first part of this sentence is good, "Kicking off the ground, she went into a sprint once more." but the second half use a weak verb when a plethora of stronger words are readily available. Try this, "She dove into a renewed sprint." Other possible words are "lurched, leapt, charged" etc. I exchanged "once more" for "renewed" just because it cuts a word.
Two things for this sentence, "The trees began to thin and soon she was in a clearing, a grassy plain. " First, it's passive again (I apologise if I sound like a broken record.) Instead of "and soon she was in..." Try "and soon she burst into..."
Second, the words "clearing" and "plain" are no synonymous. A clearing is a small clear space in a forest. A plain is a huge, flat tract of land. Even if they were synonymous, though, having both would be pointlessly iterative.
I have two small suggestions for this next sentence, "She turned around, and brandished a long spear like weapon taken from her back." First, "turned around" is much like "continued" up above. It's a perfectly acceptable action, but it's also kind of inert unless the scene modifies it somehow. I would suggest changing it for some like more exciting like "spun" or "twisted." This is purely personal preference, however. Second, I think this sentence flows better if you change the "and brandished" to "brandishing." My reasoning for this is that "she turned around" is a very short action without a huge amount of weight. By linking it to the subsequent phrase, you broaden her action, giving it more meat. (if that makes sense.) Again, that just personal preference. (Also, "spear like" shoulder be "spear-like")
You might be able to remove this sentence, "Deep in the dense forest this weapon's effectiveness was severely hampered." Most readers will consider this thought on their, so you probably don't need if for that reason. A reason you might want to keep it though, is because her previous comment "this seems like enough space..." gives the indication she plans something larger and the comment about the spear/unname weapon clarifies that she has no such intention.
So, two things for this sentence, "They were ugly creatures, bipedal beings with green skin that were of short stature." First, you can remove the second "were" with a little rearranging. "They were short, ugly creatures, bipedal beings with green skin" or "they were short, ugly creatures with two legs and green skin."
Second, you described them as a stampede up above, but that now seems incongruous with the reality of goblins. When I think of the word stampeded, I think of huge creatures that trample everything in their paths. Goblins can't trample anything really, they would have to bend and race around everything.
This sentence is mostly unnecessary, "Goblins, is what they were known as." I would just migrate the "goblins" over one period and connect it to the previous sentence with a colon. Delete the rest.
Result in something like, "They were short, ugly creatures, bipedal beings with green skin: Goblins."
(Also, I just realized something. If Goblins existed in our world, they would inhabit Australia because in popular mythology they always come from "down under" :D)
You have two separate actions/descriptions in this phrase when only one is necessary to convey your point, "...holding clubs and swords that they swung around with reckless abandon." Instead of holding, just say "Swing their rough clubs and sword with abandon." (the word "reckless" is already inherent to the "with abandon."
It might benefit the reader if you were to describe her weapon. Is is a spear with a long, sword-like tip (also known as a glaive I believe) or more axe like?
I would exchange "get" for "land" here, "before the new few foes could get a single hit in she spun."
This sentence makes cements the incongruity of stampeding goblins, "They outnumbered her, but they were weak and clumsy." If they're weak then they can't stampede properly.
This sentence contradicts what follows, "In the midst of this battle a thumping noise caught her attention." In the next sentence, you have her killing the final goblin so it's hard for this to be the "midst of battle" which refers to the middle of a conflict rather than the tail end of one.
Also, start a new paragraph with the large goblins arrival to give his appearance greater impact.
The whole remainer of the paragraph is a little clunky, but it also lacks impact. I'm just going to combine my suggests for ease.
"Just as the last goblin had fallen a much larger monster emerged. It too was a goblin, only it's size was ridiculous. Twelve feet tall, with limbs as thick as logs. Barely able to stand on her feet, the woman stood her ground as the large goblin closed the distance between the two of them. It swung a large club at her side, she used her weapon to guard it, yet the force was too much. Unable to fully block the attack, she was blown backwards. Her weapon flew from her hands, and she violently rolled across the grassy plain before finally stopping."
My (light) suggestions,
"She staggered back as the last goblin flew and braced her shuddering limbs with her spear" (By interrupting the smooth transition from one conflict to the next, you give the large Goblins arrival more tension and danger while also singling it out)"A thundering step sounded in the battlefield's silence, followed by the crack of tree limbs" (Here, I foreshadow the big guys arrival to let the tension and threat build. This lets the reader anticipate so his appearance will give a small jolt of satisfaction.) "She turned back the forest, bracing herself as the new monster emerged." (Here, you will surely note, I used turned instead of a more energetic action. This was intentional because it builds into the theme of her exhaustion. It's lack of energy now becomes a sign of exhaustion, which in turn compounds her peril.) "It was also goblin, but it towered over the rabble that lay dead around her and moved on tree-trunk limbs. She braced herself, holding her weapon out before her and waited. The monstrosity charged and swung at her with a club larger than she was. She twisted, holding her weapon out to block, but its club slammed into her and crashed through, flinging her across the field. She slammed into the ground, losing her weapon, and rolled onward." (Rolled onward is a weak action for what should be a violent series of blows, but I just didn't like how careened flowed in that situation.)
For this sentence, "The woman lunged straight towards her foe..." "straight towards" is inherent in "lunged." I would remove.
You don't need the "from her sleep" here, "The sound of a man's voice fully roused the sleeping woman from her sleep."
This sentence is wordy, clunky and passive, "She was laying on a sheet which had been stained by the gore she was covered in." Try, "She lay on a sheet stained with the gore of her battle."
You have an errant capitalised "the" here, "Oh, The name's Gregor Stone by the way."
I would remove this "she said" here, "'I want the ability to change things. To help people.' She said" Because you already have a speech designator before this bit of dialogue with "she decided."
You might be able to reword this for a more streamlined approach, "the leather that was bound to the metal pole." Try " the leather wrapped metal pole/handle."
I don't know how many people would recognise a naginata by name, but you might want to consider just naming it immediately just to save yourself from having to write the clunky "her weapon" every time.
You don't need this "coming" so I would just remove it, "I've got some men that wouldn't take too kindly to their job being taken coming."
This is a new person speaking, it has to start its own paragraph, "Gregor called out to her while he was still unloading boxes. "There's a well down this street and to the left, by the way."
This bit of detail feels irrelevant and is kind of boring, "The capital was an enormous city that was shaped like a square, with its perimeter made of towering stone walls." I would probably just cut this. Know the city has walls, we will assume it's huge and we have no interest in its shape unless that shape is interesting (like a triangle or something unusual.)
So that's about it. I stopped commenting on the passive phrases and what not because it would just be more of the same. You have a couple telling phrase that I would like to see removed, and a few unnecessary words/iterative phrase but for the most part it's just the passive wording that you need to work on. It chills out a little as the story progress, but it's still prevalent throughout.
Beyond that, the world you started to show us is interesting and the characters you've presented us with are likeable. You've introduced conflict and objectives and hinted at a potentially awesome protagonist. Most importantly, it sparked my interest and actually involved me in the story. I don't know if you have subsequent chapters up, but I would probably read them.
One thing to consider, though, is to be careful to distinguish yourself from all the RPG animes.
I hope you find my review useful and wish you nothing but the very best of luck. :)