...Okay, this is a bigger problem, then. Your readers have the wrong expectations.
If school is a small part, if it isn't the majority or the genre of the novel, then you should not mark the novel 'School Life' genre. Same with romance. Instead, replace with tags, like the 'Romantic Subplot' tag, or a school based tag. And explain this in the synopsis; your story is not focused on a guy at school. It's about a guy named Arian learning about the fantasy world and going on adventures with his teacher. Or whatever else the plot might be.
The genre and synopsis is what the entire novel is focused on. You want to tell that to your readers quick, so they know what your story is about, without being confused.
The problem with the beginning of your novel is also about expectations. It looks like the king is the protagonist, it starts off with him, and it looks like a dark, medival family war novel. But it's not. Then don't pretend it is.
Turn that chapter into the prologue, and start chapter one with Arian, seven years later after the event with the king. Then readers will have the right expectations and will not be confused. And readers who like what you provide, will stay.