Salutations!
Congrats on getting your story out there, always good to see a new fantasy novel on the scene! I've read through what you have so far, and I'd love to share what I thought with you.
To start with, I like the way you set your scenes. I can see what's happening in my minds eye and I can't tell you how much I appreciate that you started with two major characters and a skirmish, than a whole mess of characters. It makes the whole narrative easy to follow and Ciara and Alaster are very distinct so I never mix up their dialogue. (You would not believe how often that happens even in published novels.) I also like that you start us in the middle of an action scene and your main character isn't waking up, looking in the mirror, or having a nightmare. (This happens WAY too often in Fantasy and YA novels. So much so that literary agents will, more often than not, toss a novel that starts that way and send you their dreaded "thanks but no thanks" email in response) It's very nice to find ourselves right in the middle of the action.
To that end, I did notice something slowing down your action scenes: Passive Voice and too many words. To give an example using the work itself:
"Demoralized Inamians that witnessed Alaster’s rampage started to step back and waver."
I feel as though I've been pulled out of the action so that the big words in the sentence can compete with each other. These words being: Demoralized,Witnessed, Rampage, and Waver. This is something lots of authors struggle with and if you want the king example of this, look at any of the books filed under: Eragon. Aside from Paolini's blatant theft of fantasy elements, even by name (think Maud Dib and Bid Maud. I will never not be irked by that) his over descriptive prose in the midst of action really killed any sense of urgency. (Note: this does not make him the worst author ever, or mean he lacks all potential, it just means that his book suffered from flaws that he should've had an editor for. That's more his parents failing than his, if you know his history.)
An example of how the same thing can be said and get the same point across:
"Inamians stumbled out of the path of Alaster’s rampage."
This keeps me in the action. It also tells me that yes, the Inamians are terrified. They're not sticking around to fight, they're tripping over themselves trying to get away. You say the same thing but in the vein of "show-don't-tell." I know it doesn't have larger more beautified words but, when it comes to action, the panache that fantasy is known for in terms of word usage gets in the way. It slows the action down and I begin to check how many pages a fight lasts or skip ahead so I know when the end of the scene is coming. If I'm skipping ahead, you've already lost my attention as a reader.
Now, I do have a tool here to help you with identifying passive voice and some advice to help you see it in your writing, if you don't have access to the tool. Some words to watch out for are: Was, is going, while, and -ing words. Never add an -ing where an -ed does the same job. -ed tends to keep the reader in the moment. Now, if using an -ed requires that you use more words, where using an -ing allows you to be more succinct, go for the -ing. Be sparing in your use of -ly words. They can also take you out of the moment and often, you have to add an -ly word to a sentence, meaning you have an extra word describing something you're already...well describing. Case in point:
"-it bore what looked like stone fangs almost completely covered in moss and so time worn one might confuse them with stalactites-"
Now, this description is happening during an action sequence, so it bumps me out of the action, and it's too long in describing the mouth of the cave. Adding "completely" to the sentence between "almost" and "Covered" is unnecessary because you're already in the middle of stating that it's "almost covered" in moss. The best way to keep the clip of your story quick, because you're in the middle of the action sequence, would be to shave down how many words you use to describe the cave.
"-its stalactite fangs half covered in moss-"
What this sentence does, is it assumes the reader is paying attention. Anything covered with moss is a casualty to the march of time. The reader knows this, so you don't have to mention that it's time worn. Two, it also keeps the pace of the moment quick because you're in a battle and can't wax poetic. The entire pace of the scene should be considered when you're doing something as fast paced as a battle. Now, on to the tool you can use to help with the passive voice (which, incidentally, can help you identify moments when you've used too many words to describe something): EditMinion. Boy do I love this little guy! It's a great guide to help you tighten up your narrative and keep things quick without sacrificing the meat of your story! It just helps you find other words or identifying ways of describing a situation that best fit the tone of a scene.
This thing also gate keeps the Passive Voice like no tomorrow! Now, another tool I like to keep on hand, even though this pertains more to Query Letters than the novel itself: QueryShark. In identifying problems with a query, you can also identify problems with a narrative. Often times this comes down to being more precise in word usage and I've found it's a great tool to give you an idea as to your trouble spots, when you can see them happening in other works.
All that being said, you've still got a promising story here and it's clear you enjoy what you're putting forth. You should! Despite that action sequences have a little hitch, you've still got an interesting character in Alaster who seems to enjoy a laugh more than he does bashing heads. It's also interesting to see that he's more sympathetic to the first Inamian he comes across like he would be to another human, despite that he's been in bitter conflict with them. I also like that Ciara, although mistrustful, is still willing to help Alaster out even if she's not 100% on his side. She seems like someone who'd rather err on the side of caution than end up at a knifes end. This is an interesting conflict that I'd like to see play out.
Their dynamic is a great one to start with so, all in all, you've got a good beginning. I'd just look for ways to trim down unnecessary words or over-embellished ones that don't add to setting the scene. They can gum up the entire narrative and have people skipping ahead to see how long a scene might last. I hope the tools I've posted here are helpful! I really love using them, and they help me keep myself in check.
I wish you all the luck as you continue to write!