Who is Tauriel??
She's not in any of Tolkien's writings, but rather the writers created her to add a heroine to the mainly male cast.
“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.”