One of the earliest recurring characters in the Marvel Cinematic Universe was killed off fairly early on — Agent Phil Coulson of SHIELD, who made appearances in Iron Man, Iron Man 2, Thor and The Avengers before getting killed off in that last one. He was then resurrected in the TV series Agents of SHIELD, but the movie producers don’t consider it canon.
Today, Marvel began an interesting campaign to celebrate 10 years of Marvel Studios films. This all began back with Iron Man back in 2008, and since then has grown to encompass many movies across many different Marvel properties. A special picture was released, called a “class photo”, that highlighted many of the actors, actresses, writers, and directors that helped make this all possible. However, there were many notable exclusions from this photo, including Agents of Shield star, and early MCU character, Clark Gregg.
In Avengers, easily one of the most shocking moments was the death of Phil Coulson, who had been a fun character that was created specifically for the Marvel Cinematic Universe. In fact, he was the first man from SHIELD we met. His death inspired the Avengers to truly come together and work as a team.