When one thinks of Marvel's versions of Superman, it doesn't tend to lead to warm or affirming places. The best of them, Gladiator, is strong and loyal. However, he's also arrogant. In fact, his abilities depend on him staying overly confident. Likewise, every version of Hyperion tends to be flawed; it's just a matter of whether that flaw ends up being the "you're kind of a jerk," "you're so dedicated to being a hero you don't mind becoming fascist along the way," or, simply, “you’re a murderous monster” varietal. And then there's The Sentry, a hero so dangerous that the entire universe had to forget him -- multiple times -- lest one aspect of his personality destroy everyone.
They might all have Superman's power levels, but they can't come within a football field of touching his morality or humanity. However, there is one who does. And it turns out he's older than any of the others.
Adam Brashear was born in Chicago in the 1930s. Despite being a black man in a pre-Civil Rights era United States, Brashear managed to pursue academic success. A child prodigy, he attended Cornell University. There he played football and graduated with high honors on his way to acquiring two more degrees, PhDs in theoretical physics and electrical engineering.
He came back from the Korean War a hero, with two Silver Stars to his name. But, more importantly, he met the man who became his best friend, Connor Sims. The two joined Project: Perseus, a top-secret endeavor to harvest antimatter to create an endless power source. Instead, the experiment went awry, affecting both Brashear and Sims. Sims seemingly dissolved only to come back as a twisted and cruel version of himself, the villainous Anti-Man. Brashear, on the other hand, became a living antimatter reactor. He used those powers as the hero The Blue Marvel.
To find the closest incarnation of Superman that Blue Marvel matches, think the Kal-El of Superman and the Authority. While that interpretation of Superman came after Blue Marvel debuted, they mirror each other well. They're both aging heroes today, a bit grey at the temples but still intelligent and powerful despite being somewhere in their tenth decade of existence. Both were friends with President John F. Kennedy. Both stopped actively being a superhero because of Kennedy. In Superman's case, it was the President's assassination. In Blue Marvel's, it was Kennedy asking him to step down because the U.S. was not ready to accept their greatest hero was a black man.
In the years after his exile, he'd make occasional appearances only to disappear again after the crisis was averted. These brief appearances included the destruction of an alien armada, a team-up with Blade and some other heroes of the 70s, and the defeat of an interdimensional being known as the Infinaut.
When Brashear finally returned to being a hero, to defeat his former best friend one last time, he decided not to recede to the shadows. While America still has tremendous and devastating issues with racism, the country had nonetheless changed enough that the hero no longer felt an obligation to maintain his hiatus.
Since his return, he's joined the Avengers and the Ultimates, helped prevent World War III, talked with the Watcher on the ocean floor, and tangled with the likes of Doctor Doom and Galactus. Through it all, the Blue Marvel repeatedly chose the more difficult but less violent path, trying to save villains from themselves as much as defeat them.