Expelled from Hogwarts. Condemned to Azkaban. Erased from memory. Sagres Greengrass—a name that once echoed through the Wizarding World, spoken in hushed tones of dread and reverence. Half-blood heir to a pure-blood legacy. Spell-crafter of unthinkable power, inventing incantations too dark to voice. A prodigy who shattered every boundary chasing forbidden knowledge—and suffered the consequences. Labeled a threat, he disappeared into Azkaban's depths. Now, five years later, he emerges—no longer as a student, but as a professor. Sagres Greengrass is a transmigrator. Born into pure-blood aristocracy, his introduction to magic came through his mother's Cruciatus Curse. When he turned to his father for salvation, he discovered the truth: his father walked as a Death Eater. Azkaban's walls did not corrupt or shatter him. Instead, they forged something far more dangerous—a chilling grace born of survival. Armed with dark secrets, a mind honed by suffering, and knowledge only the most sinister wizards possess… The Dangerous Genius has returned.