The main character of this doujinshi novel was the male protagonist's rival, Voldemort.

He wanted to transmigrate.

Answer 1

"Voldemort in Douluo Continent" is a light novel written by the author, Ji Ji. The general plot of this novel is as follows:

His name was Tom Marvolo Riddle. During the martial soul awakening ceremony, he didn't have a martial soul. Under the strange gazes of others, he remembered who he was. He was the Dark Lord, Voldemort! He had failed, but the heavens had given him another chance. He wanted to rule this new world and make everyone afraid of him. They wouldn't even dare to mention his name…He had once received a prophecy that only one of them would survive, between himself and Harry Potter. He had now received another prophecy,"Between him and Tang San, only one person can survive."…This time, Voldemort would be the final victor.
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"The Deep Sea Wizard of Hogwarts" was a light novel by the author, Orange Orange Youzi. The plot of the novel was as follows:

Compared to beauties like Hermione and Luna, or the main characters like Harry and Ron, magic was obviously more attractive. This was the story of an otherworldly visitor at Hogwarts who had established a blood curse with a slippery evil god. "Compared to the guy in my body, Voldemort is like a good baby." Boss Ke, who was forced to live in the main character's body: "GroGros, you deserve to die!"
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Hogwarts: The Awakening of the Dark Arts was a light novel by author Wang Samar. The general plot of the novel was as follows:

Voldemort: I will not die, but as long as I do not die, it is the greatest curse in the world!
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My Father Is Voldemort was a fantasy-epic fantasy novel written by the author, Lion of the False Sun. The general plot of the novel was:

Yala lived a simple life, almost bored to death. On his 18th birthday, he received a mysterious gift, a tour of the Harry Potter world.
The story unfolds from this moment. He unexpectedly comes to the world of Harry Potter and becomes a boy who should not exist.
"Wait a minute, I'm Harry's brother! But..." Yala suddenly felt the shadow behind him surge. The corners of his mouth cracked open, and his expression of grief and indignation instantly froze.
Voldemort laughed at the boy's dumbstruck expression. "Son, I should congratulate you on gaining Dumbledore's trust."
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"The Ancient Warlock of Hogwarts" was a light novel by the author, Du Shanbao. The general plot of the novel was:

Where did wizards come from? What was the nature of magic? Andre, who came from another world, walked into Hogwarts with his own questions. Voldemort was just a small wave in the vast history, and there were bigger waves waiting for Andre in the future.
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"HP Demon King's Transformation Guide" was a light novel by the author, Wu Wang Hao Liang. It was a doujinshi derivative novel. The general plot of this novel was:

Cedric Diggory was dead, Fred Weasley was dead, Sirius Sirius Black was dead, Headmaster Dumbledore was dead, Professor Snape was dead…
It wasn't until later that I realized that as long as Voldemort was defeated, the plot would be nothing.
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Learning Magic from Hogwarts was a light novel written by the author, who had a new brain. The general plot of the novel was as follows:

In the beginning, facing Voldemort's "beauty" attack, Noah, who had almost become the youngest Death Eater in history, let out a shout that belonged to a transmigrator."We have a grudge!"
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Hogwarts: The Synthesis of All Things was a light novel by the author, Earthgazer. The general plot of the novel was:

Moss Kennington was the First-class Merlin Medal winner, the messenger of peace, the great author, and the most popular wizard in the eyes of ordinary people. When he puts on the mask... Weasley Brothers: He likes pranks as much as we do! Dumbledore: Moss is a boy who craves affection! Snape: He's full of grief! Lockhart: He's a liar like me! Voldemort: Moss is a dark pureblood! Grindelwald: .. Moss: Yes, you're all right. [New book: I'm really not a dating system.]
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Harry Potter: The Illustrated Book of Fantastic Beasts was a light novel by the author, Zhuan Zhu. It was a derivative doujinshi novel. The general plot of the novel was as follows:

Had he transmigrated and become the grandson of the Neute family? All the major cities are looking for me? And Voldemort wants revenge on me? Dave waved his wand, and the Phoenix, Thunderbird, and Lion Dragon appeared behind him.
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Hogwarts: I Am Voldemort was a light novel by the author, September Life. The general plot of the novel was:

I, Voldemort. The holder of the yew wand, the owner of the six Horcruxes. Descendant of Salazar Slytherin, the Dark Lord of the Death Eaters. Director of the Hogwarts-Azkaban Branch Admissions Office, leader of the Wizard Death Squad. The Magus World! I'm back!