Every superhero fan has to have a favorite. Mine just happens to be a loser.
That would be Wonder Man, the title character of the newest Marvel TV series — and the very last one greenlit before Disney mandated a less-is-more approach to the MCU on television.
Wonder Man, aka Simon Williams, was introduced in one of the very first issues of The Avengers, back in 1964, as a new villain who poses as a good guy to infiltrate the Avengers, then sides with them against Baron Zemo and dies in the process. He was meant to be a one-shot character. But for reasons too petty and nerdy to get into here, he was resurrected a decade later, and reimagined as a hero with the power of a god, but feet of clay. His powers were so derivative that his awkward catchphrase for a while was, "My fists hit as hard as Thor's hammer!" He sometimes froze up in battles, and generally felt unworthy of being on the same team as the likes of Iron Man. For a long time, he didn't even wear a traditional costume, going on adventures in a red safari jacket and black turtleneck, plus red sunglasses to conceal his glowing red eyes. (This was arguably his best look; the man's had a lot of awful, awful outfits.) He's been on and off the Avengers ever since, almost always presented as a C-lister who dreams of just making the B-list. Most of the time, he's used the way Star Trek: The Next Generation used Worf, as the guy who gets beat up at the start of a battle to let you know how powerful the villain is. He has died multiple times, often being out of action for years before another writer remembers he exists and brings him back from the dead yet again.