On Friday morning, Marvel made a huge announcement on Twitter, and fans are not happy.

Marvel Entertainment is joining forces with Northrop Grumman, an American global aerospace and defense technology company, and the world's fifth-largest defense contractor.

We don't know much yet, but it looks like there will be a promotional comic featuring the Avengers and "Northrop Grumman Elite Nexus," or N.G.E.N.

The arms manufacturer generates over 20 billion dollars in revenue a year. Marvel Entertainment didn't reveal anything more about the partnership, and to learn more the company encouraged fans to head to their New York Comic Con booth on Saturday afternoon.

The partnership comes as a surprise to many Marvel fans. Tony Stark/Iron Man, one of Marvel's most popular characters, stops selling weapons (his family's long-time business) because he realizes he's not saving lives, he's destroying them. For sensitivity reasons following the Las Vegas shootings, Marvel pulled its NYCC panel for "The Punisher," and canceled screenings of the first two episodes.

Many lauded Marvel's decision to cancel The Punisher screenings, but fans don't seem pleased with the new Northrop Grumman partnership, and some took to Twitter to express their opinions on the matter:

The full details of the partnership are unknown, but more should be revealed on Saturday at NYCC.