Kristoff's backstory in Frozen includes being raised by trolls, but how did he come upon these magical creatures in the first place? Kristoff Bjorgman (Jonathan Groff) was first seen in the 2013 film's opening scene as a small child following an ice team with his beloved reindeer Sven. One could tell from his enthusiasm how much he wanted to be a part of the team, but the sight of Arendelle's royal family rushing by distracted him. Following their caravan, Kristoff and Sven ended up in the Valley of the Living Rock, home of the magical rock trolls. A troll named Bulda found the adorable pair in the Frozen opening, and she quickly decided to "keep" as her own.

While Frozen shed some light on the Sven and Kristoff backstory, much of it was still left ambiguous, such as why the pair decided to leave the trolls behind and set off on their own adventure. Frozen's story is told mainly through the eyes of Anna and Elsa, so it makes sense that more of their backstory isn't left to the imagination. However, Kristoff and Sven have become popular characters in their own right, with many wanting to know more about their origins, outside of Anna. Here's everything that's known about Kristoff Bjorgman's backstory, including why he stayed with the trolls, his true parentage, and his age.

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Why Kristoff And Sven Stayed With The Trolls

Sven and Kristoff in Disney's Frozen

The Kristoff and Sven decision to stay with Bulda and the trolls is never explained in Frozen. From the opening "Frozen Heart" scene alone, it could easily be assumed that Kristoff was a relative to one of the ice harvesters. Frozen's benevolent trolls certainly would not kidnap a child (unlike the trolls found in Norse mythology), which the movie draws from. In fact, Kristoff told Princess Anna (Kristen Bell) that it was "just him and Sven" when he was adopted by trolls. Kristoff seemingly grew up among them happily and freely, and even as an adult, he valued his found family in spite of their eccentricities.

The confusion of the Kristoff and Sven backstory was cleared by Frozen's director, Jennifer Lee, in interviews. She confirmed that Kristoff was an orphan at the start of Frozen, and not related to the ice team from its opening. He always loved the outdoors, and refused to stay within the confines of the orphanage, and preferred to watch the ice harvesters or hike out in Arendelle's vast wooded landscape instead. His childhood wandering led to him meeting Sven for the first time. Kristoff being raised by the Frozen rock trolls was a product of his own curiosity leading him to them. His exact reason for staying is unknown, but it can be inferred that he would prefer their company over staying in the orphanage because of their open-air forest dwelling.

Kristoff's Parents And Age Are A Mystery

'Frozen' Kristoff and Sven

Love is one the trolls' core values, as demonstrated in the "Fixer Upper" number, and they were quick to shower Kristoff with it. Growing up among them, he learned troll customs, including their coming-of-age ritual, which he continued to value as an adult. In the tie-in book Frozen Northern Lights: Journey to the Lights, Kristoff took Anna, Elsa, and Olaf back to the Valley of the Living Rock to assist in such a ceremony for his close childhood friend, Little Rock. However, it is unknown whether Kristoff and Sven themselves underwent their own rite of passage.

Despite Frozen making his emotional connection to his adoptive family clear, Kristoff's biological parents remain a mystery. They received little acknowledgment in Frozen II or any of the franchise's spin-off books, leading fans to theorize he could possibly be related to the Northuldra people seen in the sequel. They were shown to have the same affection for reindeer as Kristoff, but the question of any deeper connection was left open-ended. Much of Frozen's related media has unveiled new pieces of Anna and Elsa's backstories, and with the franchise's continued popularity, it will likely continue to expand. There is certainly room for the Kristoff and Sven origins to get the spotlight in the future.

Related: Frozen 2's Ending & The Fifth Spirit Explained

A Frozen Theory Suggests Kristoff Isn't An Orphan

Frozen
This image released by Disney shows , from left, Anna, voiced by Kristen Bell, Olaf, voiced by Josh Gad, and Kristoff, voiced by Jonathan Groff in a scene from the animated feature "Frozen." (AP Photo/Disney)

There is a Frozen theory floating around that Kristoff's parents are still very much alive, and could make an appearance in Frozen III. What's even more interesting about this theory is that it could connect Frozen to other Disney movies like Tangled and The Little Mermaid. Given the significance that is placed on Anna and Elsa's parents in Frozen, introducing Kristoff's parents would bring an entirely new perspective about his history that couldn't be explored through any other main character.

Frozen heavily explores themes of heredity and family, and it's interesting that Kristoff's place in this hasn't been inspected thus far. By showing the perspective of parents who were separated from their child, Frozen could also solve a conundrum that the film has inadvertently brought about: the depiction of trolls in Frozen versus how they are explained in Scandinavian culture. In Scandinavian folklore, trolls are actually much more untrustworthy than Frozen makes them out to be, and having Kristoff being taken and hidden from his parents by the trolls would close that gap.

It's been theorized that Frozen connects mainly to Tangled and The Little Mermaid through Elsa and Anna's parents. The theory posits that King Agnar and Queen Iduna were taking a journey to attend Rapunzel from Tangled's wedding when their ship crashed, which was later discovered by Ariel in The Little Mermaid. Frozen 2 essentially disproved this theory by stating that the King and Queen's shipwreck happened north of Arendelle, but since no one knows the identity of Kristoff's parents, this theory could be passed on to them instead. The earliest plan for Frozen was to connect Hans Christian Andersen's The Snow Queen tale with the rest of his stories, like The Little Mermaid. However, Disney took a lot of artistic license with The Snow Queen, and it's uncertain whether the original Frozen plan is still in motion. Either way, Kristoff's parents haven't been explored yet in the Frozen universe, so their story could be connected to anything at this point.

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