8 things we just learned about the 'Harry Potter' universe from J.K. Rowling's latest e-books

Pottermore just released three new ebooks with new information about the “Harry Potter” universe.

Under the “Pottermore Presents” banner, these new books are mostly filled with entries and information that we’ve seen before on the site — but there are some interesting new nuggets.

Here are the most important things we learned about the “Harry Potter” universe from “Short Stories From Hogwarts of Heroism, Hardship and Dangerous Hobbies,” “Short Stories From Hogwarts of Power, Politics and Pesky Poltergeists,” and “Hogwarts: An Incomplete and Unreliable Guide.”

McGonagall didn't join the Order of the Phoenix at first because she was spying for the Ministry of Magic.

Warner Bros.

While we know in 'Harry Potter and the Order of the Phoenix' that Minerva McGonagall was new to the Order, we didn't know why she didn't join during Voldemort's first rise to power.

'Short Stories From Hogwarts of Heroism, Hardship and Dangerous Hobbies' reveals that McGonagall was a spy for the Ministry of Magic during that time. Though she was a teacher at Hogwarts, she previously worked at the Department of Magical Law Enforcement, and it looks like they called in a favour and had her use her Animagus powers to transform into a cat, collect information about Voldemort's followers, and bring that information to the Ministry's Aurors.

The Ministry saw the Order as a renegade outfit -- ministers were still cagey about Dumbledore possibly wanting their job -- so it wouldn't be possible for McGonagall to work for both the Ministry and the Order.

Death Eaters killed Professor McGonagall's first love.

During Lord Voldemort's first attempt to take over the world, Death Eaters went on random anti-Muggle killing sprees. During one of these sprees, they killed McGonagall's first love, Dougal McGregor.

McGonagall never married him because she knew it would be difficult for them to have a life together: she was a witch, he was a muggle looking forward to inheriting his dad's farm. But after his death, she wondered if she could have saved him if she married him.

After the Battle of Hogwarts, McGonagall appeared on chocolate frog cards.

Warner Bros.

Appearing on chocolate frog cards is a fairly big deal in the wizarding world. The cards are collectible items and show history's greatest wizards and their accomplishments.

McGonagall added Snape's portrait to the gallery of headmasters and headmistresses only after consulting with Harry.

Warner Bros.

It was a controversial decision. His true roll in Voldemort's demise was not widely known at first, and it's easy to see how some people might have viewed Snape as a puppet for Voldemort, especially for allowing Death Eaters to teach classes at Hogwarts.

So McGonagall consulted Harry about it. Rowling writes that McGonagall was uncommonly close to Harry not just because of their shared experiences and because his parents were two of her favourite students, 'but because he, like herself, had suffered serious bereavements.'

Harry. of course, said yes.

It's insanely hard to become an Animagus.

Warner Bros.

In 'Short Stories From Hogwarts of Heroism, Hardship and Dangerous Hobbies,' Rowling goes through the steps of how to become an Animagus, or a wizard or witch who can transform into an animal at will.

Unsurprisingly, it's really, really hard. There are ten steps to becoming an animagus. Here's the first one:

'1. For the space of one entire month (from full moon to full moon), a single leaf from a Mandrake must be carried constantly in the mouth. The leaf must not be swallowed or taken out of the mouth at any point. If the leaf is removed from the mouth, the process must be started again.'

The rest of the process is similarly punishing. At the next full moon, you need to take the mandrake leaf and put it in a vial filled with your saliva, then mix it with dew 'from a place that neither sunlight nor human feet have touched for a full seven days,' among other ingredients. That vial has to be placed somewhere where it can absorb the rays of the full moon. If it's cloudy that night, sorry, you have to start over again.

After that, you need to wait for a specific kind of storm to come before you can proceed to step three. If it doesn't come for years, you just have to wait. You get the idea.

Professor Slughorn quit Hogwarts after Voldemort attacked Harry when he was a baby.

Warner Bros. Pictures

'Short Stories from Hogwarts: Power, Politics and Pesky Poltergeists' goes into the backstory of Horace Eugene Flaccus Slughorn, Harry's sixth-year Potions Master.

Slughorn was important because, as Tom Riddle's teacher, he told him about horcruxes and therefore might have helped him become immortal.

After Voldemort's fall, Slughorn was relieved. If Voldemort was really dead, he reasoned, then he couldn't have made horcruxes.

Nonetheless, 'it was Slughorn's extremity of relief, and the disjointed phrases he let fall in the first rush of emotion after hearing of Voldemort's defeat, that first alerted Dumbledore to the possibility that Slughorn had shared Dark secrets with Tom Riddle,' Rowling writes. Dumbledore tried to question him, and Slughorn clammed up, then quit his teaching job after 50 years at Hogwarts.

One of Voldemort's Death Eaters tried to recruit Slughorn.

Warner Bros.

After Harry returned from the Triwizard Tournament in 'Harry Potter and the Goblet of Fire' saying that Voldemort was back, the Ministry dismissed him.

But Slughorn believed Harry. Three nights after Cedric Diggory's death, the Death Eater Corban Yaxley 'arrived at Slughorn's house under cover of night, clearly intending to recruit him, or take him by force to Voldemort.'

Slughorn went on the run, hiding in muggles' houses and evading the Death Eaters until Dumbledore found him and, with Harry, persuaded him to return to Hogwarts for Harry's sixth year.

Slughorn's bravery changed the stigma toward Slytherins.

Warner Bros.

Slughorn was a Slytherin, the Hogwarts house commonly considered to be the 'bad guys' in Rowling's world. But Slughorn complicated the moral guidelines of the 'Harry Potter' universe.

As Rowling writes, 'Slughorn's genuine remorse for the damage he had done in telling Riddle what he wanted to know is conclusive proof that he is not, and never was, Death Eater material. A little weak, a little lazy, and certainly snobbish, Slughorn is nevertheless kind-hearted, with a fully functional conscience.'

During the Battle of Hogwarts, Slughorn -- along with Minerva McGonagall and Kingsley Shacklebolt -- was one of the last three to duel Voldemort before Voldemort battled Harry. His courage, along with that of Regulus Black, 'removed much of the stigma that had been attached to Slytherin house for hundreds of years past.'

Now his portrait has a place of honour in the Slytherin common room.

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.