Iron Fist

Iron Fist is a super hero who fights crime with martial arts. He can concentrate his energy on his fist to make it as solid as iron.

The Avengers: Earth's Mightiest Heroes
Iron Fist and Luke Cage are hired by Henry Pym to find who stole his Ant-Man equipment.

Ultimate Spider-Man
Iron Fist is part of Spider-Man's team as part of S.H.I.E.L.D. Of the whole team, he is the one who treats Spider-Man better, albeit he sometimes retaliates on Spidey the same way as the rest.