Nikolas is Elektra's father, and his death drives her pursuit of Daredevil.
The plot explicitly identifies Elektra as the daughter of Nikolas Natchios.
Nikolas serves under Fisk before becoming a target.
Nikolas is identified as Fisk's lieutenant, then attempts to end his relationship with Fisk.
Bullseye assassinates Nikolas on Fisk's orders.
Bullseye steals Daredevil's baton and uses it to impale Nikolas, killing him and framing Daredevil.
Explore the full interactive character relationship map of Daredevil