Harry Potter: The Worst Thing Every Order Of The Phoenix Member Did
3. Albus Dumbledore - Magical Supremacy
Perhaps the only other character to rival Severus Snape in complexity of character, Albus Dumbledore is an endlessly intriguing character. In the first few books, the wizened headmaster of Hogwarts is seen as almost infallible. Incredibly powerful, seemingly thinking several steps ahead of everyone, the brilliant Wizard's presence meant that nothing truly horrible could befall Hogwarts while he remained.
Looking into Dumbledore's past, however, it is evident that his calm, brilliant demeanor had been tempered over years in the pursuit of power. Feeling trapped with the burden of looking over his younger brother and sister following the death of his parents, Dumbledore took solace in fellow magical genius Gellert Grindelwald. The two then began to theorize over the wizard's right to dominate Muggles, considering their power. Dumbledore insisted all of this was for the greater good and wanted to minimize suffering, but that did not diminish his desire to rule.
Confronted by brother Aberforth over the horrors he would commit, Albus realized the implications and relented, only for Grindelwald to angrily attack his brother. Albus engaged in a duel with Grindelwald, and in the ensuing chaos, a stray curse struck sister Arianna, killing her.
This guilt has sat heavy upon the shoulders of Dumbledore ever since. Perhaps it is best that he remained a teacher in Hogwarts despite being offered positions within the ministry. Who knows what temptations that kind of power may have wrought in the intervening years?