Daredevil and Spider-Man
Both have been offered membership to the Avengers, both have declined. Spider-Man later did join briefly. Daredevil, the man without fear - lawyer Matt Murdock was injuried as a child with radioactive waste while saving an older man from being hit by a truck while crossing the street. This blinded him, but gave Matt heightened senses and a radar like power. Trained by Stick and the Hand, Matt is one of the greatest martial artist in the Marvel Universe. His power necessitates he work alone to avoid the noises and comotion a group would provide.
Both of these heroes are close friends and often turn to one another for help and comfort as they serve the dark streets of New York.
