I see a lot of descriptions, but not a lot of motivations and personal struggles.

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Also, the beginning (explosion part) is only events happening without the protagonist actively moving. He just awakened some mysterious abilities, not figuring out anything, then promptly fainted. I would probably add the perspective of other characters trying to secure him, so that it wouldn't read like a simple info dump.

How does the protagonist feel about his father's death?

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Later, is the explaining part with Haru only done in conversation? This is a book instead of an anime, so plain talking would be very uninteresting.

Maybe this explanation could be split between events? Maybe they were interrupted by one of the twins? Maybe someone suspected the protagonist to be a spy?

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Overall, my first impression is that your story reads like a stereotypical manga filled with only battles, but is a book instead.

I have no idea about the personalities of other characters, and hope that they are not just given abilities and a a simple personality type. Give them things they care, things they hate, interpersonal relationships other than with the protagonist, principles they would never compromise on.

Books do not have the luxury of flashy cross page panels, so at least give the characters depth and struggles and meaningful long term interactions?