A chapter titled "The Greater Good", reveals that Dumbledore graduated Hogwarts with many honors and accolades. He and his friend, Elphias Doge cancelled a Grand Tour of Europe after Kendra Dumbledore's sudden death. Although Doge had claimed that Dumbledore made a grand sacrifice to care for his family, the book implies otherwise, quoting several Godric's Hollow citizens. Enid Smeek recounts that Albus did little to curtail his brother Aberforth's wild behavior and kept his sister, Ariana, hidden away. Although the Dumbledores remained reclusive, Bathilda Bagshot reportedly established a friendship with the family. Skeeter claims that while Bathilda's memory may have been affected by age, she was able to extract enough facts to piece together the scandalous story of Kendra's death, which was passed off as a spell backfiring. She also debunks Ariana being sickly and claims Albus had an affinity for the Dark Arts and may have supported Muggle oppression.The same summer Albus returned to care for the family, Bathilda Bagshot took in her great-nephew, Gellert Grindelwald, a student as brilliant as Dumbledore, who was expelled from Durmstrang. He later became a notorious Dark wizard, though he was relatively unknown in Britain. He and Albus quickly bonded. In a letter to Gellert, Dumbledore writes that he agrees Wizard dominance over Muggles is for the greater good, but they must rule responsibly and only use force when necessary. He believes that was Gellert's mistake at Durmstrang, although he says that if Gellert had not been expelled, then they would never have met. Rita states that this letter proves that Albus Dumbledore once intended to overthrow the Statute of Secrecy and establish wizard rule over Muggles. It contradicts his later stance supporting Muggle-born witches and wizards and protecting Muggles' rights.

But barely two months after their friendship began, Dumbledore and Grindelwald parted ways until their legendary duel. Bathilda Bagshot believed the rift involved Ariana's death. Gellert was present when it happened, and he came home distressed, leaving by Portkey the next day. Aberforth blamed Albus, and they came to blows at the funeral. It was never understood why Aberforth blamed Albus for Ariana's death, though it is speculated that it was related to Albus' friendship with Gellert, who had been expelled from Durmstrang for near-fatal attacks on fellow students.

Gellert went on, some decades later, to head a reign of terror on the continent, eventually becoming the most feared Dark wizard in history at the time. Five years after Grindelwald's assumption of power, Dumbledore finally succumbed to the Wizarding world's pleas to end his vicious rampage in Europe. Questions lingered after Grindelwald's defeat, however. Was it Albus' affection for Grindelwald that delayed his taking action? How and why did Ariana die? Was it an accident or the first attempt at implementing their "Greater Good" plan?