The role was created by Peter Jackson and co-writers Fran Walsh and Philippa Boyens, to expand the world of the Mirkwood Forest elves. Here's what Evangeline Lilly had to say about Tauriel's role in this elf society.
"Tauriel is the head of the Elven Guard. She's a Sylvan Elf, which means she's of a much lower order than the elves we all became acquainted with in The Lord of the Rings. She doesn't hold the same kind of status that Arwen or Galadriel or Elrond or Legolas do - she's much more lowly. She sort of goes against the social order of the elves a little bit."
Although Tauriel is a fierce warrior, this character will have a love interest that plays a significant factor into the story.
"She will definitely have a love story. I can't give away too much about it. It's not a huge focus but it is there and it is important and it does drive Tauriel and her story and her actions."
When asked if this lover is Orlando Bloom's Legolas, she would not confirm nor deny, but did say that Tauriel's relationship with Legolas is significant.
"Tauriel's relationship with Legolas is significant. They've known each other since they were children, and Legolas' dad, [Elven king] Thranduil, has a soft spot for Tauriel and sees something very special in her. So if you grow up side by side, and your dad has a very special spot in his heart for this young woman who's a fantastic warrior, I think it's hard not to notice her. That's probably as much as I can say."
Since this character is a completely fresh addition, Evangeline Lilly spoke about the purists who will likely hate her character, an experience which Lost helped prepare her for.
"I know beyond a shadow of a doubt that there are going to be people who will totally hate Tauriel, think that she shouldn't be in the movie, that it's a betrayal of Tolkien, and no matter what I do it won't be right. There will be everything between that and people who adore her and think it's such a fun thing to have added to the film. I kind of got prepped for that being on Lost, because we had avid fans who were really extreme in their feelings about the show and its characters. But I think if anyone knows how to respect Tolkien, it's Peter, Fran and Phil. And Tauriel fits perfectly in that world."
The Hobbit: The Desolation of Smaug was released December 13th, 2013 and stars Ian McKellen, Martin Freeman, Richard Armitage, Ken Stott, Graham McTavish, William Kircher, James Nesbitt, Stephen Hunter. The film is directed by Peter Jackson.