About this AUEdit
In this AU, the big four are portrayed as Vikings. Because Hiccup - one of the original members of the Big Four - is in fact a viking, this AU usually involves itself within the plot of the How to Train Your Dragon series, setting the characters as members of the vikings of Berk or at least from tribes somewhere in the Barbaric Archipelago, though this is not required. Some may also use the setting and time of History's Vikings for inspiration.
The Big FourEdit
Because he is already a viking, Hiccup most commonly plays himself (much in the same way that Jack Frost plays himself in the Seasons Guardians AU), acting as future/current chief of the Hairy Hooligans and leader of the Dragon Training Academy.
In some scenarios, Jack usually portrays a viking incarnation of his original human self as either a Dragon Killer-in-Training or as a Shepherd given his crook. Should he be a Dragon Rider, people most often portray him paired with either an adolescent Bewilderbeast or a Snow Wraith given their association with ice and winter. Sometimes this incarnation of Jack dies in the same way that he does in the film, becoming Jack Frost after saving his sister.
In other circumstances, Jack is portrayed as the old nordic legend Jokul Frosti, providing a mythical angle to the overall story.
Due to her masculine, tomboyish attitude, Merida is most often portrayed as a Shieldmaiden in the same vein as Astrid. Should she be a Dragon Rider, Merida is usually either paired with a Deadly Nadder (given her similarities to Astrid), a Scauldron (given its similarities to the fabled Loch Ness Monster) or any other dragon currently unused by the dragon training academy.
Rapunzel's role in this AU is one of the trickier, as the role of women in traditional viking society was notably narrow. Should she be a citizen of Berk, she would most likely be a Shieldmaiden (though far less militant in her title as Astrid or Merida would be), her magic hair being a blessing from the gods that they worship.
Being an island goddess can easily make and cast her as the Norse Earth goddess, Jord. While her Te Kā form makes her a Fire Giant, an enemy of the Viking gods.
Elsa is mostly seen as a Shieldmaiden that was cured or had her ice powers given to her by the Viking God, Loki. Her royal states also makes her a chief of her own Viking tribe in the North and on an icy, cold island. As a Dragon Rider, her dragon would mostly be a dragon that breaths ice or live in icy habitats; like a Snow Wraith or a Bewilderbeast. Fans have also made her the rider of a White Night Fury, for the Hiccelsa pairing.
Marshmallow's large, snowy body makes him a Frost Giant from the Northen Legand.
Moana is mostly seen as a Shieldmaiden in the same vein as a female Hiccup or Astrid. She can also be the heir to her Viking traibe, when her island is placed in or near the Barbaric Archipelago and when her family and people are portayed as Vikings; as Vikings were also known for sailing and discovering new lands, like their voyaging ancestors. As a Dragon Rider, her dragon most likely be a Tidal Class dragon; like a Scauldron, Thunderdrum, Seashocker or any of the other sea dragons. As a reference to a Mo'o, a giant sea dragon that moves an island with its body.