You're wrong about how the Seal works. People leave here, they go right back to the same point in time, they can't change their own world.
I don't give a flying shit about Avengers, which is a stupid nickname in my opinion, and SHIELD is just a daft acronym. Loki is a friend to a lot of people here. He's risked his life to save ours. That's worth remembering.
I didn't introduce myself. Name's Crowley. King of Hell. Native of here.