During Sir Cadogan's period of guarding the Gryffindor common room, he changed passwords so frequently that Neville Longbottom had to write them down. This list was snatched by Crookshanks and was given to Sirius Black, allowing him entrance.
What was the password to get past the portrait of the Fat Lady?
Order of the Phoenix edit
Harry is first to the Gryffindor dorm's entrance on his first night back at school, but he does not know the password, and the Fat Lady will not let him in. Neville, arriving almost on Harry's heels, says that he will be able to remember the password this year; it is Mimbulus Mimbletonia.
It was 'Caput Draconis' which is Latin for 'dragon's head' and that definitely fits as a straightforward password for the common room. But dig a little deeper and you'll find that Caput Draconis is a key geomantic figure.
Due to his humiliation in the Triwizard Tournament, Cedric eventually becomes a Death Eater and kills Neville Longbottom. Due to Neville's death, the final Horcrux Nagini was never destroyed, and as a result Voldemort is never defeated, kills Harry and takes over the Wizarding World.
When we were first introduced to Sirius Black, he was a wanted fugitive on the run from Azkaban, convicted of the murder of Peter Pettigrew and of betraying Harry's parents. Not a good start. Sirius didn't exactly improve matters when he tried to sneak into the Gryffindor dormitory by slashing the Fat Lady's portrait.
How Does Neville Get the Sword of Gryffindor? - Harry Potter Explained
Why did Sirius rip the fat lady?
When Sirius first breaks into Hogwarts in Prisoner of Azkaban, he doesn't know the password to get into Gryffindor Tower. In anger he rips the Fat Lady's portrait. While Sirius' frustration is understandable, he was a Gryffindor. He knows the fat lady is only doing her job and keeping his beloved house safe.
Dumbledore's lack of belief that Sirius is innocent is also suspect. Sirius was a member of the Order of the Phoenix which fought against Death Eaters, but Sirius also was as close to James as a brother, the Potters even took him in when he ran away from home.
Alice and Frank Longbottom were not killed. They were tortured with the Cruciatus Curse to the point of insanity. It was a combination of Bellatrix Lestrange, Rodolphus Lestrange, Rabastan Lestrange, and Barty Crouch Jr.
Seething with fury at his humiliation, Cedric ended up joining the Death Eaters come Voldemort's return. As a result, during the Battle of Hogwarts, Cedric Diggory killed Neville Longbottom before he could destroy Nagini, thus keeping Voldemort immortal and allowing him to kill Harry Potter.
Although Peter is not "the dark lord" himself, he drives home the point that evil would be nothing without its supporters, making Pettigrew as bad as it gets. It's unclear when Peter Pettigrew turned to the dark side, but even throughout his youth, he was a follower and never a leader.
The Ravenclaw common room has no password. To enter, you answer a question and give your reasoning. There are students in the other houses who could do this, so this method doesn't keep non-Ravenclaws out.
The entry password was "Pure-blood" when Draco Malfoy let them in. The Polyjuice Potion's wearing off prompted Harry and Ron to leave after staying nearly an hour, still not finding out the identity of the Heir of Slytherin, but they did learn that Malfoy was not the heir, as they originally thought.
In order to reveal the entrance, no password was required. Instead, one had to tap the barrel two from the bottom, middle of the second row, in the rhythm of "Helga Hufflepuff", which would make the lid swing open, exposing a passageway that would lead to the basement when crawled through.
Sirius was angry and with reasons. He stabbed the Fat Lady because he wanted enter into the Gryffindor tower but he hasn't got the password (but when he had it, he could enter…even if he was, supposedly, a murder. (About McGonagall's punishment to Neville we talk other day)
Passwords in Hogwarts appeared to change on a regular basis. During Sir Cadogan's period of guarding the Gryffindor common room, he changed passwords so frequently that Neville Longbottom had to write them down. This list was snatched by Crookshanks and was given to Sirius Black, allowing him entrance.
Harry Potter had a few love interests during his time at Hogwarts. Though he eventually settled down with Ginny Weasley, he also had a thing for Cho Chang in his earlier school years. Then, of course, there's his secret love for Draco Malfoy… Wait, what?
Luna married fellow naturalist Rolf Scamander, grandson of Fantastic Beasts and Where to Find Them author Newt Scamander, considerably later in life than Harry, Ron, Hermione, and Ginny, who all married and started families in their early-to-mid twenties.
Their first kiss happens on the front steps of Malfoy Manor. Harry brings Draco his wand after speaking at his trial, “This is yours; thank you.” And this time, Draco won't let him walk away. Harry turns to leave and Draco grabs his arm, turns him back and kisses him.
Harry describes Umbridge to Sirius Black, saying that she's vile enough to be a Death Eater, despite not being one. Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.
Alongside Barty Crouch Jr., she tortured Neville's parents, Frank and Alice Longbottom, to the point of insanity by means of the Cruciatus Curse. After meeting Neville she immediately mocks him about it.
When questioned by Bellatrix about his loyalties, Snape says he has been working for Voldemort ever since Voldemort's return, and explains his actions in the previous books in that light. He points out that gaining Dumbledore's trust and protection has kept him out of Azkaban and free to operate on Voldemort's behalf.
Peter Pettigrew's betrayal of the Potters and allegiance to Voldemort was a result of his unhealthy admiration for James and desire for power. Sirius Black was believed to be the Potters' Secret Keeper, but he secretly switched with Peter Pettigrew, who turned out to be a mole.
