This blurb would tell me not to read the book. Let me see if I can break it down...

The nameless boy...

who in sentence 3 gets called "Hain". And "Hain" is consistent throughout the rest of the blurb. So, in your blurb, you already defied the narrative causality because it doesn't matter that he was the nameless boy anymore.

dreams of becoming a wise man. A dream that comes true

There's no conflict at this point; he wants, he gets. Moreover, the druid solves his original problem of being nameless, which waters down the strength of his introduction.

when he meets a druid in the forgotten forest in Mazheven

It's forgotten but it has a name...? And they were both in this forgotten forest arbitrarily, for an arbitrary meeting... my interest is waning because I have no sense of author-trust right now: your forgotten forests aren't forgotten, your nameless heroes aren't nameless, and the wisdom comes fortuitously.

The druid calls him Hain and takes him to Lárhus in Atesh

I dunno where Atesh is or its relevance to Mazheven, but it seems like Larhus is the first place that matters to the plot.

to study the teachings of past and present.

Sounds like a reason to world-build and info-dump stuff you've developed for this world. I don't really care about the world yet though...

But nothing goes as he wishes and he finds himself expelled. Not because of what he did but

He's innocent. He didn't make a mistake, he got caught in an unfortunate plot snaggling up the druid's life and affairs.

because of the intruder that broke off the spells that protected Lárhus and murdered scholars.

So you're hoping we care about the druid enough to care that the druid's facing some unfortunate complications... but like your world, I don't have a concern for it yet. This is really hard to achieve in a blurb; and so we've got Hain leaving Larhus because stuff got wrecked. Stuff he had nothing to do with. Hain doesn't make the problem, Hain doesn't care about the people being troubled, and Hain doesn't suffer much trouble for it. He's a bystander.

Hain decides to return to Aderbaal and become a druid on his own

Cool. Paragraph 1 was basically unimportant.

until then. A human-shaped raven crosses his path.

Is this your ghostpig (the weird/special/cool idea that sparked the novel to be written)? The fact we've got a deity playing in mortal affairs? Why did it take so long to get here?

It tells him to follow it to a deity that was outcasted from Atesh a thousand years ago.

Outcasted. Outcast is already past tense; I would prefer this sentence to be like "It tells him to follow an outcast deity" because it would also get rid of the "was" that is an EXTRA past tense on the past tense that is tense here. Tension's gone. I mean, a thousand years is a whole lot of time for drama to blow over, so whatever's keeping the deity in exile has basically won. Like, I have no personal interest in following the raven-guy's wish cause it seems a non-issue at this point.

The same deity that gave him a necklace the first day at Lárhus then disappeared out of sight.

This is new info to when Hain actually visited Larhus. So, not only are forgotten forests not forgotten, nameless heroes not nameless, and wishes attained with relative ease, but now deities can just retcon in giving away necklaces. Cool............................................

Now Hain must decide what to do, either leave for Aderbaal or follow the raven and find out more about the deity he thinks is the intruder.

Do his own thing or else follow up on the first half of the blurb? I'd hope the answer would be following up on Larhus, since it took up so much blurb-attention, but honestly, I doubt I'd open the book to find out.

I think you could make the blurb way more exciting via Hain having a personal connection/concern for the plot, whether that's making the druid a family member or a love interest, making Hain responsible for the problems at Larhus somehow, showing the deity as a more present, relevant being, or else by revealing the Actual Ghostpigs of this story, but I suspect the problems I've noticed here run deeper than just the blurb.

Sorry bro, I can't fix this one for you.