Hogwarts AU

Hogwarts AU is a popular AU (Alternate Universe) within the Rise of the Brave Tangled Dragons fandom. In the AU, Rapunzel, Merida, Hiccup and Jack Frost are all students at Hogwarts School of Witchcraft and Wizardry. Because it is not canon, ideas for this AU are shown through fanfiction, fanart, and other fan-made works. Hogwarts AU is considered to be one of the most popular scenarios in the RotBTD fandom today.

About the AU
The world of Harry Potter has been a popular universe for all fans to use for crossovers, and this is especially the case in the RotBTD fandom. Hogwarts School of Witchcraft and Wizardry is the perfect location for the Big Four to interact because of a number of reasons: it is an educational institute that gives an excuse for the four to be in the same area, it allows for the use of magic and the idea of dragons, and it adds elements of competition and rivalry between the Big Four and their friendship.

In most cases, being being Sorted into separate Houses along with other characters from their respective movies allows for relationship development in unique and creative ways. However, there are few authors that do Sort them all into one House to set the rationality of their closeness as friends. Because of how Hogwarts separates their Houses, there is a sense of rivalry between them, and its students rarely get to meet up at the same time outside of double classes.

Featured Characters
While most often sorted into Gryffindor for their heroics, the Big Four are often seen Sorted in separate Houses as a means to create a sense of camaraderie, "Breakfast Club"-style. Some House choices are universally accepted, whereas others are more debatable.  

Hiccup Horrendous Haddock III
Hiccup is a hard character to Sort from the group and often debated among authors for where he truly belongs. He possesses the hardworking and loyal nature of a Hufflepuff, but also contains the thirst for knowledge and quick wit that is admired and portrayed by many Ravenclaw students. In his feature film, How to Train Your Dragon, he is shown to be intelligent, observant, and clever, as well as being able to use his friends and their dragons' weaknesses and strengths to defeat the Red Death.

Often in this universe, he is known to still have Toothless as a pet dragon, going through the same befriending and training as his film, but within the Forbidden Forest.

Jack Frost
Jack is commonly Sorted into Slytherin for his mischievous and sometimes destructive nature which is seen more towards the start of his feature film, Rise of the Guardians. As a result, many stories feature him as a darker, more angst-ridden character compared to the other members of the Big Four, using his Sorting as a point of tension and plot drive. He is usually given a spot on the Slytherin Quidditch team as a Chaser or Seeker, creating a competitive spirit between him and Merida.

Other stories and artists have portrayed him as a Gryffindor, showing him more as a fun-loving trickster to replace the Weasley Twins or the Mauraders. This takes into account his traits of being brave and daring, his more heroic traits he developed near the end of his film.

Depending on the fanfiction, Jack is sometimes returned to his regular mortal state as Jackson Overland in order for people to see him and for him to attend school. On the other hand, regular magic-users might not have a problem believing in and seeing a spirit like Jack, and therefore some writers leave him as the white-haired Jack Frost, even having him fall into the lake beside Hogwarts to receive immortality. His staff is also sometimes converted into a wand to fit within Harry Potter canon, although this is not always the case.

Merida DunBroch
Merida is almost always sorted into Gryffindor, due to her bravery and sometimes foolhardy courage. Gryffindors are seen as strong-willed and sometimes do not think all of their choices through. This often is justified by the character traits she takes on near the end of her feature film, Brave. Alternatively, some people have Sorted her into Slytherin because of her ambition, resourcefulness, and self-centered desires, though it is not the primary choice.

Quite often in the fandom, Merida is shown to be on the Gryffindor Quidditch team, usually against Jack as a Beater or Chaser. She also is shown as not being the most astute student, often forgoing homework and studying for more exciting activities. Occasionally she even takes up archery outside of the classroom.

Rapunzel Corona
It is widely disputed on whether Rapunzel should be in Ravenclaw or Hufflepuff, as she possesses qualities indicative of both. As shown in her film Tangled, her creativity, thirst for knowledge, and her drive to know more about the world outside her tower could sort her to Ravenclaw. However, she also has the traits that could place her in Hufflepuff, such as loyalty, honesty, and patience. Additionally, she is often portrayed with her long blonde hair, however there are some artists that include her with her pixie cut. It is up to fanfiction writers whether her hair is as long or as magical as it is in the movie.

The Founders
Due to the recent popularity of the film Frozen, they've been added to this story as the founders of the houses but there descendants are also in the current generation of Hogwarts students:

Kristoff Bjorgman
Kristoff is portrayed as Godric Gryffindor, founder of the House of Gryffindor.

Queen Elsa of Arendelle
Elsa is portrayed as Rowena Ravenclaw, founder of the House of Ravenclaw.

Princess Anna of Arendelle
Anna is portrayed as Helga Hufflepuff, founder of the House of Hufflepuff.

Prince Hans of the Southern Isles
Hans is portrayed as Salazar Slytherin, founder of the House of Slytherin.

In Progress

 * The Big Four Chronicles: Legend of the Golden Flower by ayoungwriter
 * The Big Four, Hogwarts Day by InfiniteShadowRealm
 * Chamber of Nightmares by FantasYAnDMadnesS
 * Clever, Cunning, Brave and Loyal by kai1234
 * Dangerous Doors by hiccups pickle
 * The Four Legends by Silver Star Lake
 * The Golden Four by Tomcat2425
 * Hogwarts Meets the New Generation of Troublemakers by Chiaki Hamano
 * A Hogwarts Story by Palleas
 * Making Magic by Animaneya
 * Rise of the Brave Tangled Dragons Hogwarts Edition by goaliegirl12
 * ROTBTD: Hogwarts Storybook by LegendaryRaconteuse
 * When Worlds Collide by siiixmehh
 * Of Magic and Mischief: A Big Four Story by Lighty7
 * ROTBTD: The Return by The Alliance's Loyal Thief

Complete

 * The New Generation of Troublemakers in Hogwarts by ayoungwriter (Discontinued)
 * ROTBTD: Four Against Fear by LegendaryRaconteuse
 * The Big Four and the Sorcerers Stone by F-A-Jackson
 * Fire and Sun by chasertiff
 * I'll catch you if you fall by changeofheart505
 * Potion Mishap by SmilesBerry
 * The Big Four and the School for Witchcraft and Wizardry by theohbm