Imagine: Walking into S.H.I.E.L.D. for work, you are greeted by a black haired man inside of a glass prison.
"Uh...Who is he and why is he in a glass prison? Coulson?" You asked, very confused as the man looked at you.
"Loki. He tried to lay waste to New York City." Coulson replied with disgust.
"Oh." You turned to look at the man. "Hi."
Instead of saying anything, he slowly flashed a wide grin. Strange. He probably wasn't expecting an actual introduction.