Adrian, an orphan who grew up at Hogwarts.
At five, Dumbledore found him and brought him back to the castle. He ate with ghosts, lived among portraits, and received private lessons from professors in every subject: the sole student in Hogwarts' elite in-house program, with all the credentials to prove it.
When he turned eleven, the headmaster said, "Time to go to school. Start in first year."
So, concealing the necromancy he dared not let anyone see, he disguised himself as an ordinary first-year and walked onto Platform Nine and Three-Quarters.
Then he met Hermione Granger.
A top student who had read all the textbooks in advance.
A stickler who could fire back ten retorts for every one thing he said.
A know-it-all who hit especially hard.
"Why haven't you done your homework again?!"
"I did. I just didn't do it right."
Hermione picked up Hogwarts: A History and smacked him in the face.
That was the first time. It certainly wouldn't be the last.
When the Chamber of Secrets opened, when the Dementors arrived, when the Dark Lord returned...
The grinning boy wiped the smile from his face and took out the ebony dragon-bone wand he'd hidden in the Room of Requirement.
"Allow me to introduce myself. This is my old line of work."
At the boundary between life and death, the dead whisper.
Necromancer, at your service.
In fact, the original part is just the main plot. I have read more than ten Hogwarts fanfics, so I automatically skipped some of the original content. The original part is well written, and the character of the protagonist is very interesting.
This book reads differently from other Harry Potter fans. The text has a prose feel.