Cosplayer is Nadine Howell.
Elektra Natchios, usually referred to only by her first name Elektra, is a fictional character appearing in publications from Marvel Comics.
Elektra is a kunoichi – female ninja assassin – of Greek descent. She wields a pair of bladed sai as her trademark weapon. Created by Frank Miller, Elektra first appeared in Daredevil #168 (January 1981). She is a love interest of the superhero Daredevil, but her violent nature and mercenary lifestyle divide the two.
Elektra was born on a Greek island near the Aegean Sea to Hugo Kostas Natchios and his wife Christina Natchios. She had an older brother named Orestez Natchios.
Two contradictory accounts of her family history have been given. In Elektra: Root of Evil#1-4 (March - June 1995), Christina is killed by assassins hired by Orestez, while in Elektra (Vol. 2) #18 (May 1998), she is killed by an insurrectionist during the Greek Civil War. In both accounts, she gives premature birth to Elektra just before dying.
When a nine-year-old Elektra was assaulted by kidnappers, the men were all killed by Orestez, who had grown into an accomplished martial artist after leaving home. Orestez advised his father that Elektra needed to learn self-defense. Hugo hired a sensei to teach her the martial arts. (Wikipedia)