About this AU Edit
Shingeki no Kyojin (known to English-speaking audiences as Attack on Titan) is a popular manga series that has also been adapted into an anime series. The series follows Eren Yeager, his adopted sister Mikasa Ackerman and their childhood friend Armin Arlet, who have lived inside the massive protective walls throughout their lives, in a fictional world taking place "to you, two thousand years later." These 50m high walls were built to protect the humans from nearby Titans, large, human-like giants that prey only on humans. At the start of the series, the wall around Eren's city is destroyed, creating an entrance for the Titans, whom then attack the city. During the tragedy, Eren witnesses his mother get eaten alive, and swears to kill all the Titans to avenge his mother. To do so, Eren, Mikasa and Armin train as soldiers and join the military.
Most fanworks show the characters in the universe with no role as a certain character (example: Merida as Mikasa), and so far, it is not known which characters play which roles. In this universe, it is more of them living in the world with their own stories.
Younger Hiccup most fits the role of Armin Arlet, as both are intelligent and try to find creative solutions to their problems. Older Hiccup can also represent Eren Yeager except his titan form mostly has retractable teeth base on Toothless.
So far, Jack seems to play the role of Eren Yeager, as both characters dealt with the loss of their loved ones, and have a strong connection with their sister (Eren with his adoptive sister Mikasa, Jack with his sister).
Merida is also debatable. Merida could also play the role of Eren, as both can be rather aggressive; however, Merida could also be Mikasa, as both are well-trained fighters and both are willing to sacrifice for the ones they love.
Rapunzel most fits the role of Historia Reiss, as both are royals that were unaware of their royal status, and have a interest in reading.