Harry Potter: My Father Is Grindelwald

[Two Dark Lords + Transmigration + Coming of Age + Hogwarts + Serious Tone]

I transmigrated and became a baby in the wizarding world, locked away in a cell at the top of Nurmengard's highest tower.

The one who found me was the first Dark Lord, Gellert Grindelwald.

He didn't kill me. Instead, he taught me Wandless Magic, Occlumency, and the secrets of the Deathly Hallows. He said, “You are my son, but you will go to Hogwarts and see whether Dumbledore deserves to possess the Elder Wand.”

On September 1, 1991, I boarded the Hogwarts Express and became a classmate of Harry Potter, The Boy Who Lived.

I hid my identity and pretended to be an ordinary Slytherin. But every year, whenever danger struck, the Chamber of Secrets, the basilisk, the werewolf, Pettigrew, the Triwizard Tournament, the Department of Mysteries, the Astronomy Tower..., I had to use the skills Grindelwald taught me.

Dumbledore saw through me, but didn't expose me.

Harry suspected me, but chose to fight by my side.

After Voldemort's return, I had to make a final choice between two Dark Lords, two eras, and two destinies.

When Voldemort's wand pointed at my adoptive father, I tightened my grip on my own wand and stepped in front of him

“You can't kill him. Only I can judge him for his crimes and punishment.”