Hogwarts: I Became the Second Dark Lord

(Not invincible, not wish fulfillment, not brainless, no System, female protagonist.) Suggested new title: I Play Detective Conan at Hogwarts. Noir Engel, dark beneath his fair exterior, is the grandson of the former Dark Lord and Dumbledore's future successor. His carefree life is shattered by an unexpected prophecy. His brother is captured by Grindelwald, and he grows up under Dumbledore's care. Grindelwald returns to the Wizarding World with his followers, the Acolytes, and throws it into turmoil. With their help, the battered Russian bear reunites, ready to liberate the whole world. War in the Wizarding World and war in the non-magical world are on the brink of breaking out... Harry Potter goes to Slytherin