Fusor (Bio).

A reporter in the audience raises her hand. Sol can see her heart, beating. Irregular. Not the product of a disease, just simple fear. He can see the chemical impulses in her brain that cause it, too. So fragile.
"Fusor. I-I don't mean to be rude, but... what are you?"
It's 1941. Superhumans aren't very common yet. The Supra-Man exists, yes, and a select few others, but not many.
"This is an important question to me," the Living Sun says, smiling. "So forgive me if I'm a little long-winded."
He takes a moment to draw breath.
"In roughly ten-to-the-hunredth-power years, the universe will finally die. Entropy will consume all light, life, matter, and energy in existence. Humanity may not be around by that time, but... I will be. My powers aren't just 'super-strength' and 'laser vision,' they come from a well of energy within me.And that well is infinite. I could use my powers for thousands of years, and never run out of power. That limitless store of energy, of 'negentropy,' is what will sustain the universe. And while it continues, while I live, we have hope. That's what I am, ma'am. I'm hope."

Name: Sol/Saul.

Fusor, the Living Sun.

Though he was once a 'super-hero,' Sol is, first and foremost, a utilitarian, concerned with doing the most good for the most people. So, when he was presented with the opportunity to help countless billions of future lives, he agreed, regardless of the cost to himself. He sealed himself in a chamber built to absorb as much energy as he could output, so it could be funneled into a massive 'battery,' which would provide clean power for future generations, when the unrenewable resources of the day were exhausted.

Abilities.

Boundless Energy.

Sol's body is a living generator, capable of outputting literally infinite amounts of energy. By nature, he violates the Law of Conservation of Energy, in producing such raw power. How this is possible, no one knows, but it has the potential to make Fusor one of the Earth's most powerful champions.

Formidable Physiology.

However, on it's own, simply producing energy is not enough to make Sol that powerful. A nuclear power plant doesn't fight crime, after all. But Sol does not simply output that energy, he also uses it. His entire body is supercharged, muscles surging with the power of stars, his brain moving thousands of times faster than that of the average man. Sol can control the amount of energy he allocates to his muscles, giving him fine control over his own strength. If he wishes to hold back, he won't afford himself much power at all, and if he wishes to go all-out, he's capable of breaking worlds.
To match his strength, Sol also has speed. While humans are limited in speed by the amount of stress their muscles can take, and the amount of energy they have to spend, Sol is bound by neither. As such, he moves faster than almost anything on the planet. He can't be outrun, even by the fastest being on the planet, because he can simply increase the amount of energy he uses, and thus increase his speed.
Thanks to his unparalleled control over his own body, Sol also has a vast suite of super-senses. His eyesight can see down to the level of electrons, and though he can only see what he's looking at, his hearing, sense of smell, and hyperawareness of his surroundings, he essentially has something akin to three-hundred-and-sixty-degree vision. He can produce Röntgen radiation, or 'x-rays,' allowing him to see through matter, as far as he likes. His hearing can distinguish individual footfalls and heartbeats out of billions, and his hyperawareness means he can't be caught by surprise.
As untold numbers of motivational speakers have said, the brain is your strongest muscle, and the same holds true for Sol. With infinite energy, his brain operates faster than the speed of thought, allowing him to consume information incredibly fast, as well as perform cost-benefit calculations in his mind before making choices.

Energy Manipulation.

It would be a mistake to think this is Sol's only talent. Superhuman strength is impressive, but on its own, it does little to distinguish him from the dozens other super-strongmen out there. What Fusor can do that they can't, is control energy. With his body a limitless generator, he can produce all sorts of energy, including standard 'lasers,' but extending to more exotic kinds of energy. As evidenced by the symbol on his chest, he can make use of radiation, as well as fire bursts of kinetic energy, and mimic the solar rays of the sun.
When fighting, Sol usually projects his attacks from his eyes, in part to suggest his powers are similar to that of his contemporary, Supra-Man, but he's not limited in this way at all. He can project energy from any part of his body, and has been known to shine brightly with all his body, resembling a star both in appearance and average energy output.
Though his ability to fly seems unrelated to his other powers, it's not. One of the many kinds of energy Sol can output is a hereotfore-unknown particle he's dubbed an 'anti-graviton,' which has the effect of reversing gravity's hold on the Solar Sentinel. Once in the air, he can propel and slow himself by increasing or decreasing the amount of anti-gravitons he's outputting.
Though Sol's energy manipulation seems best suited for offensive combat, he can also make use of it defensively. When facing opponents who use energy-based attacks, even those commonly thought of as 'magic,' he can simply absorb it. It doesn't make him any stronger, because the amount of energy he produces naturally dwarfs that of most other superhumans, but it negates any harm that lasers, or magic, or anything similar might do.
A less commonly displayed facet of Sol's energy-manipulation power is his ability to heal and empower. Either through physical contact or proximity, he can 'give' energy to those around him, accelerating their bodies' natural functions much like his own. When they're injured, he can speed up their healing, and when they need a power boost, he can provide it. Unfortunately, when projecting this effect as an aura, it's indiscriminate, meaning he'll heal enemies as well as allies. He most often uses it after battles, as he has the time to sustain physical contact with the injured. During the second World War, however, he was known to walk through hospitals or trenches, healing the sick and injured simply with his presence.

Fighting Style.

Being a utilitarian, Fusor is well aware of the potential collateral damage of a drawn-out fight between two people of his capabilities. As such, his fighting style has no regard for honor, or civility. When the stakes are serious, he becomes a brutal, ruthless fighter, who won't hesitate to kill, if it will save more lives than it will end. If he's entering a fight with an opponent he intends to kill, he will immediately go for a killing blow, rather than drawing the conflict out needlessly. When he can't immediately kill a foe, he'll aim to incapacitate, through whatever means necessary. Most superhuman combatants are so used to fighting those weaker than them, that they don't expect to be debilitated, such as having their arm broken, and Sol takes full advantage of this fact.

Paraphernalia.

The Suit: Though it's designed to be aesthetically pleasing, and comes with a cape, the black suit that Sol wears is built to allow the most energy to escape his body. It was designed by the Solar Sentinel to aid in his mission to provide power to the world, but also doubles as a 'super-suit,' thus explaining the radioactivity symbol emblazoned on his belt.

Chronology.