Harry Potter, Save Quirrell at the Beginning

In the 19th century, the Dumbledore family experienced a split. One of them had a very famous descendant, Albus Dumbledore, who was known as the greatest wizard. He also had a younger brother, Aberforth Dumbledore. Both of them thought that they were the only two members of the Dumbledore family, but neither of them knew that there was another family named Dumbledore in London. It wasn't until Cassius Dumbledore's name appeared in the Hogwarts Admission Book that Albus Dumbledore knew there were descendants of the Dumbledore family. Calculated by seniority, Cassius should be Albus's grandson. Later, Cassius completed seven years of schooling at Hogwarts. During these seven years, Cassius's strength grew to After Cassius graduated, Albus arranged for him to go to the Albanian forest to find Voldemort, who was already vulnerable at that time, because Cassius's Animagus was an eagle, making it easier to find high in the forest. But just a year after Cassius graduated, Albus wrote that the boy who survived would enroll at Hogwarts this year. Albus hoped that Cassius could return to Hogwarts to take over the position of Professor of Defense Against the Dark Arts and protect Harry Potter. Cassius readily accepted Albus's request and returned to Hogwarts again, but on the way back he saw Quirinus Quirrell, the former Ravenclaw senior.