I have three concerns with what I have read.
The first is that you're posting your work on (ugh) FanFiction.net . You have clearly developing talents, and I think they are wasted on that horrific medium. It is a place for bad writers to hang out, not good ones. They don't even let you make proper
paragraphs for christsakes! Try putting your work in PDF format, as much for yourself as for your readers. You'll get a better sense of how your prose reads if it were in a real book. That helps more than you might think.
My next concern is the premise of your story. You establish things very quickly from the villain's perspective and reveal a substantial portion of their plans and motives right off. That's really not good policy if you want to maintain an element of mystery, discovery, or surprise, which is rather important in any novelistic endeavor. Another foundational problem is your plot device of "Lets use the heroes to get (x) of something because we (presumably) cannot get them ourselves." This plot has been used so many times, particularly in video games, that I cringe every time I see it pop up. I want to take Lucca's Wondershot and riddle it with blaster bolts.
My third concern is how you portray the battle of chapter 3 playing out toward the end. Seriously, is this the same team that vaped Lavos in Chrono Trigger? They don't seem to do all that well against these small-fry. But more important than that is how you have enemy reinforcements pop up out of nowhere to give the villain an easy win while the heroes just look on helplessly. If the enemy has the power to do
that, why do they need Lucca and company to fetch relics? This plot device has also been done to death in video games. You need to ask yourself if you're playing a video game or writing a story. I understand the need to give the player things to do in a game by making them fetch (x) of something to accomplish (y). Is that an interesting way to approach a story? I mean, we can already see how things will play out. The heroes collect the relics, the enemy gets what they want, the heroes engage in a titanic battle to stop the now-stronger villain and somehow win where they couldn't before, and life goes on. Am I missing anything?
I don't mean to seem overly negative with these points, Grace. A lot of young writers fall into these traps. But it's best you become aware of them early so you don't start developing bad habits. Stories are very hard to fix if you have a bad foundation. Take this from someone who knows.
More positively, your descriptive prose is very good, especially considering your age. I'm envious. If I had your level of talent at age 15, I'd be a much better writer today - and I don't consider myself a slouch in that department. The best advice I can give you is to expand your horizons and envision narrative situations that can turn into single-spaced chapters of ten pages or more. To do that, it is best to keep character front and center and not feel pressured to rush the plot. After all, who cares about plot if the characters aren't interesting?
To give you a little bit of direct help, I noticed a line of dialogue from Glenn in chapter 3 that could do with some revision.
"She possesses thine traits as her mother, yet she carries much determination."
Translated from Shakespearean English, this line makes little sense. Just using the word "thine" does not a proper medieval sentence make. (For future reference, the word "thine" is only used preceding a word with a vowel sound.) Try replacing it with this:
"She possess the traits of her mother, determination being the most fully passed, though the others be hardly lacking."
Read this way, your earlier description of Glenn's medieval dialect being less prevalent in his speech is more clearly demonstrated, but he still does not speak in a contemporary fashion.
