Marvel's Batman joins the Avengers

gamesradar.com:

With Moon Knight taking up his share of media buzz, you've likely heard the character referred to as "Marvel's Batman." And though there are some fairly vague similarities between the two, Marc Spector and Bruce Wayne are pretty different in terms of personality and backstory. However, there is a Marvel character who was originally an unabashed clone of the Dark Knight, and in April 20's Avengers #55, he joins the Avengers. 

Be warned, some spoilers are going to follow, however, if you’ve checked out Marvel's April 2022 solicits, you already know which character we’re talking about.

But just in case...

Before we get into why he's joining up, we’re going to come right out and tell you; the Avengers' newest member is Nighthawk.

Originally created in 1969 by Roy Thomas and Sal Buscema, Nighthawk was a member of the Squadron Sinister, an evil analogy of DC’s Justice League. The team included the Superman knockoff Hyperion, Green Lantern copy Doctor Spectrum, and Kyle Richmond, AKA Nighthawk, a non-powered, billionaire villain that mimicked Batman.

The team of villains proved fairly popular at the House of Ideas and, eventually, their villain status was changed. A heroic version of the team known as the Squadron Supreme was introduced in 1971, then reimagined once again as darker, 'mature' superpowered characters in a 2003 series by J. Michael Straczynski and Gary Frank published by Marvel's then adult-oriented MAX imprint. Though the characters were still "heroes," the series was a lot grittier.

(Here's the full story of the Squadron Supreme, Nighthawk included).

Just like the rest of his teammates, Nighthawk’s story went from supervillain to superhero to antihero, breaking out of the mature-reader book into his own series