The Secret World of Arrietty AU

The Secret World of Arrietty AU (also known as Borrowers 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 play roles from The Secret World of Arrietty. This can be considered an offshoot to Studio Ghibli AU and Fairy Tale AU.

Jack Frost
For Jackunzel he's cast as Shawn, a young sick boy that uncovers the 'little people' from his mother's stories. Jack can also be cast as a borrower and a male Arrietty.

Rapunzel Corona
For Jackunzel Rapunzel is portrayed as the young (and just started) borrower, Arrietty as she grows close to the human boy that saw her; as he kept her a secret from his family.

Astrid Hofferson
Fans have cast Astrid as Arrietty, with Hiccup as Shawn.