Deacon was born to rule a kingdom of magic and splendor, and he wouldn’t have it any other way. Except his parents won’t stop hounding him to choose a queen in a land where getting married means an irreversible connection of mind, body, and soul.(This is going to sound really nit-picky cuz it is- but since agents are notorious nit-pickaholics, "except" is an awkward word choice given you don't state that having a queen is a prerequisite to becoming or being the ruler of the kingdom. Therefore, it has no connection to the preceding sentence. Unless you mean something more to the effect of: The only problem/issue/challenge Deacon has is his parents won't stop...) The idea of sharing a consciousness repulses him. That is, until he meets Eloiny.
Having visions of the future is the most envied of all the gifts, but Eloiny doesn’t see the point in being a Seer if she has no effect on the outcome. As much as she tries to prevent it, the boy she loves accidentally crosses the forbidden wall of magic that separates her kingdom from The Veil, a barren wasteland no one ever returns from. Willing to do anything to bring him back, Eloiny crosses the wall and
she discovers The Veil for what it really is: a prison. And Eloiny opened opens the cage. (Don't prisons usually have cells, not cages? The use of the word "cage" is confusing. So is the jump to past tense here. Also, I added "Eloiny crosses the wall" because I assume that's what she does and think I read that in a previous version AND given she's opening a cage she must be there, but the sentence as written is a little choppy and unclear IMO. I actually think the sentence would be stronger if you started with the subject: Eloiny will stop at nothing to bring him back and crosses the wall, only to discover The Veil for what it truly is: a prison. But then that begs the question- if no one ever returns from The Veil, how does Eloiny? I swear I'm not trying to be a bitch... I actually love your concept. I'm just trying to think of what plot/story issues agents might spot with their eagle eyes)
After centuries of imprisonment, the Shade, the shadow (THE Shade, THE shadow back to back feels clunky to me) of a power hungry king twisted by dark magic, wreaks havoc across the kingdoms.(Was the Shade what was in the cage? That's a bit unclear. If so, her responsibility in releasing him gives you a great opportunity to show her personal stakes in defeating him. You could add that to the final paragraph. Presuming he was in the cage, how about something like this: That cage held the shadow of a power-hungry king twisted by dark magic, known as a Shade. Released after centuries of imprisonment, he wrecks havoc across the kingdoms- siphoning magic from the lands and threatening to tear apart the fabric of time.) He siphons
the magic from the lands, threatening to tear apart the very fabric of time.
When Deacon proposes to Eloiny, she has no choice but to accept. She doesn’t want to let go of the boy she risked everything to save, but she isn’t strong enough to kill the Shade on her own. Only by uniting their kingdoms and powers will Deacon and Eloiny have enough strength to defeat an evil as powerful and ancient as the stars.
CROWN OF ASH AND STARS is a dual POV YA Fantasy complete at 80,000 words.
As a lot of other posters have already said, you've clearly got an amazing concept and I'm not even a tiny bit surprised you're already a successfully published author. My only fear (in terms of what I've learned about/read agents are looking for in a query) is that this seems to lay out most of the story arc. I'm sure the veterans on here can speak to this with much more authority than I can, but I thought you were supposed to delve about 1/3 of the way in max, and end leaving the agent wanting to know what happens, what choice the MC or MCs will make. In this circumstance, we already know they are joining together to battle the shade and save their kingdoms. I know you've reworked the last section a lot already, but I think you might be able to reword it in terms of choices and consequences that allow for more suspense. Will Deacon do A or B, resulting in C or D? Will Eloiny... Any way you shake it, I look forward to reading it once it's on the shelves. :)