Phil Coulson (Agents of S.H.I.E.L.D.)

Overview
Originally a supporting character in the Marvel Cinematic Universe, Phil Coulson was a top ranking S.H.I.E.L.D. agent and a highly skilled operative, often appearing in the background and in cameo roles in various films as Nick Fury's right hand man. He has since assumed the position of Director of S.H.I.E.L.D., replacing Fury.

Unlike the vast majority of those characters in the Marvel Cinematic Universe, Coulson did not began life in the comic books but was an original character created specifically for the movies in a very minor supporting role portrayed by Clark Gregg.

However, he quickly became regarded as "the S.H.I.E.L.D. Agent" and has had cameo roles in nearly every single MCU film. He has transitioned into becoming a supporting character in the Marvel Comics-verse and has had numerous appearances in other Marvel-based animated cartoons and television series with a starring role in Marvel's Agents of S.H.I.E.L.D.