Salutations! Okay I've read through your work and I've some feedback for you! I'll start with technicals and story implementation!
Very first on this list is actually the first sentence that threw me. In the first paragraph where Branden is searching corpses, you state that he's "-of nineteen years of age". You don't need two usages of...well, "of". You can say "Branden was a young knight of nineteen years" because it's the same thing, and you don't have an extra "of" to derail a reader. Now, one of the other things is that, you start us off in a sequence where two people are searching bodies, but then we suddenly get an exposition dump about how Branden became associated with Karn and has no noble house. This is not a good transition. I was chucked out of the scene to be given backstory we don't yet need.
I'll give an example of setting so you know what I mean. We start with these guys searching corpses looking for a mage. This would be the right time to bring up the rarity of mages and what they're for (because you do this after you exposit about Branden's backstory) so that we, the reader, have context as to what Karn is looking for. It's more important in this moment than Branden's backstory, because we're literally in the middle of a scene, which you then pause to tell us information that has nothing to do with this direct moment, so we lose our story momentum. Now, if we were back at camp and Branden was thinking about his father and why he'd come to serve Karn at the kings order, that would work because people become pensive when staring into a campfire. However, randomly while on a mission makes the exposition feel forced and out of place, when the context of the mage in this case is more important.
Now, I noticed a lot of your issues in a single paragraph all cropping up at once. So, what I'll do is paste your paragraph below and paste an edited version, and explain the edits. Here we go!
Original: "I am going to go check on Lord Hywin." Sir Jason stood up smiled and walked into the tent, Sir Karn joined Branden handing him a horn of wine. "Aye boy, you alright?" Karn asked as he took a deep sip of wine, Branden nodded and drank his wine. "Where is Lord Hywin?" a voice yelled, "Lord Hywin" it yelled again. A man dressed in leather armor with a fur cloak carrying a satchel, darted towards the fire. He was mid thirties with a scruffy beard. "Where is Lord Hywin?", "In the tent" a knight pointed out. "Thank-you kind sir" he said then he walked into the tent, a few minutes later out came the three men. Lord Hywin walked towards the fire "you can all leave, return to your own holdings." he commanded. No one asked why and they all headed in separate directions, "King's orders," Karn said before he vanished from sight.
Edited: "I am going to go check on Lord Hywin." Sir Jason stood up smiled and walked into the tent, Sir Karn joined Branden handing him a horn of wine.
"Aye boy, you alright?" Karn asked as he took a deep sip of his own, Branden nodded and drowned the images in his head with his drink. The camp was quiet, the normal chatter now a mumble as the air stank of death. Two miles north of the carnage wasn't far enough to make camp so far as Branden was concerned. Not even alcohol could purge the memory of spilled blood from his nostrils.
"Where is Lord Hywin?" yelled a man dressed in leather armor with a fur cloak. He carried a satchel and an intent mien as he darted towards the fire.
"In the tent" a knight pointed out.
"Thank-you kind sir" he said as he ambled through the canvass flaps without introduction. Sir Karn alert at the sign of this messenger, got up from his seat at Branden's side and followed after him into the tent. Moments later Lord Hywin emerged with the messenger and Sir Karn at his side as they approached the circle of knights by the fire.
"You can all leave, return to your own holdings." he commanded.
"King's orders," Karn said before he vanished from sight. The gathering remained mute, uneasy glances traded from one knight to the next.
Phew, okay, so you'll notice I've done a few things here. To start: I put everything in bold that you repeated throughout the paragraph. Using the exact same descriptors (such as "walked") for every motion puts everything in your narrative on repeat and it can actually make someone put your novel down. I made it to this paragraph before I had to stop and start writing my feedback, because you have many instances of repetition that distract the eye, but they all culminated pretty heavily in this paragraph. Using different words to describe action can tell the reader a lot. What if the messenger was running? Was he urgent? Was he out of breath? Were his cheeks red in the dim light? All of these little things can tell us if the message was important. Which, seeing as how when the messenger showed up everyone effectively lost their job, that'd be pretty important. So telling us that he "walked" everywhere doesn't really let us know if the message is urgent, so we, the audience, don't know how to feel. It's just a thing that's being told to us.
Likewise, I feel no urgency or impending dread here, which I should feel if everyone loses their job suddenly without warning. That's a huge red flag that something has gone wrong, yet I didn't feel that way. I just felt like everybody in camp wasn't even there or listening to begin with. Part of the trouble here is atmosphere. To establish atmosphere you have to let the audience know more than the base facts such as, there's a messenger, there's a message, and you're all jobless. Are the knights singing around the camp fire, being drunk, being solemn, is everyone quiet for no particular reason, is there a sense of dread, unease, what does the wind smell like, fire or death? There are SO many things missing here that can make your audience FEEL the moment.
When I edited the paragraph, I interpreted the scene as solemnity because, really, I had no indications for or against it, I just ran with it because you didn't tell me what was going on. You did say Sir Jason and a few men around the camp fire talked about their families and triumphs, but I still had no idea what the general feeling of the scene actually was. They've been finding innocent people dead for days, with no sign of letting up, yet I still felt nothing. I was just told that Sir Jason told a story and some men talked shop. In fact, this scene is a better moment to introduce Brendan's backstory because he can become pensive thinking about his own family when others are bringing up theirs.
This is where we get into "Show don't Tell" as well. You told me a lot of things, but you didn't paint the scene. You told me that we were in camp, that a messenger came, and Brendan doesn't have a job now. You also told me that the knights all dispersed without a word. Now, I don't live in a caste system, but when a company I used to work for had massive layoffs, people were pretty vocal about it and these people were all loyal. Karn didn't have to quell unease or questioning, there were no rumblings of discontent after the announcement, just nothing. No feeling at all, so suddenly the scene itself isn't important. It just felt "meh, okay" and that was it. So far, you've got scenes, but they just feel like a list rather than a narrative. "Thing A happened, so now thing B can happen, followed by thing C." It's not very engaging.
I've also noticed that you spend a lot of time describing people's beards as "scruffy." There's only so many times that can be used before it becomes too well worn. A Thesaurus is a good tool to help you find other descriptors if you find yourself at a loss. Don't go Thesaurus crazy, though. Some descriptors work and some don't depending on their definition so, whenever you look up a new word, take it over to the Dictionary to determine whether or not it makes sense in your context.
Another trouble we run into is that you overuse people's names after they've been introduced. Notice how, in your paragraph I bolded Lord Hywin's name? You said it the exact same way five times in a single paragraph. I was able to get the same point across in my edited paragraph without having to state his name over and over. Again, this comes down to narrative flow and what distracts readers, and overuse of a character's name is one of those things. I'll make an example so you can see right off:
I live with my roommate Jim, Jim is good at X. I'm trying to work on projects with Jim and while I'm very busy Jim likes to laze about. Jim isn't very good at staying on task, but I like Jim. Jim's got a good sense of humor.
See how distracting that is? It's the same principal. You can indicate who is talking or who is important in the scene without so much repetition. Likewise in Tullec, in your very first paragraph you use "edge" as a descriptor three times in four sentences. So, I'd recommend making sure you're not repeating yourself or your descriptors too much in single paragraphs. It's an easy habit to slip into so, getting out can be tough but it is totally doable. Speaking of paragraphs. See how in my edited version of your paragraph, I started a new line with every new speaker? This is done to prevent audience confusion. I actually didn't know clearly who had been saying what before, because it was all within the body of a single paragraph. Hitting enter and starting your dialogue on its own line is the best way to keep it all straight for a reader, and it makes your narrative flow more easily.
Now, I'm not going to leave you high and dry without editing goodies! First off Editminion. This handy tool gives you a heads up on adverbs (-ly words which should be used sparingly if ever, because they can take your narrative out of Active Voice and turn it into Passive Voice). It can also help you with seeing if words are being repeated, misspelled, or if you're ending on a preposition. It's a handy little tool that can make editing WAY faster. Now, on to the next bit, here are some resources to help you construct atmosphere, paragraphs, and dialogue with regards to paragraphs.
Phew, okay, that was a long bit. Still, I hope these resources help. Honestly you've got a good premise (and I'm a sucker for mages. You should see all my Dragon Age series quests) and I think that you can make a good go of your story. You've got some editing to do, but that's the nature of writing novels. EVERYBODY has some editing to do, not just you, and we ALL run into the repetition problems and atmosphere issues. It's just part of the process, so you're already doing exactly what you should be. Don't feel discouraged at the amount of editing or the what, because we all do it just the same. You're going to make something awesome happen here and you'll get there in your own time. You got this!
Also, fair is fair. My work also needs a lot of editing right now, but you're welcome to check it out and give me feed back as well. After all, we're all conquering this thing together. (Don't forget to read my description, if it sounds like something you won't like, it's totally fine if you don't want to read it).