When you say "Marvel or DC type" do you mean using their characters or just examples of possible characters?
In fact, I'm going to toss up an idea or two- let's see what happens.
Magic, the Gods, Monsters, Supernatural Creatures- in short, they exist. Sort of. Not all of them exist, and those that do are rarely as big a deal as advertised, but there are more then a kernel of truth to many of them. Magic, for instance- really does exist. However, it's much harder to tease it's secrets then Science and Science is about finding out how the Universe works while Magic is more about getting the rules of the universe to bend in your favor. So Magic and Sorcery are real, but they aren't as powerful as Science. They still can provide an X factor though.
Which brings us to one kind of magical being in particular, the Gods. What exactly occurred is unknown, but it appears that about 6,000 years ago a small group of human beings, scattered all around the world, were either born with or somehow acquired a mutation that is still a complete mystery. What is known is what it did to these people- psychic potential was dramatically increased, their immune systems were dramatically enhanced, their bodies were made larger and much more durable, their healing increased, and their aging either slowed to the barest crawl or stopped altogether. Technically, they aren't immortal- but killing them in a way that sticks is very difficult, if not impossible with the technology present 6,000 years ago. And when you have a few centuries to practice you can become amazingly good at practically everything. They began to see themselves as Gods, and called themselves such- whether to shepherd humanity to greatness or rule with an iron fist depended on the God or Goddess in question.
Humanity did have one advantage over the Gods however, namely breeding. Gods could only breed more Gods with other Gods. The child of a God and a Human was a Demigod, powerful to be sure but not nearly as long lived or durable as a God. And the child of a Demigod and a Human was barely any different from a Human being at all. 2 Generations and your own family could raise up arms against the Gods and side with Humanity.
The end of the Age of Mythology was marked with the revolts against the Gods. It wasn't a solid process, but it's pretty much agreed that it was all over by the time of the fall of the Roman Empire. The Gods may of been much more powerful one-on-one but the Gods and the Faithful were easily outnumbered. The humans wisely decided that while the Gods were out of power, there was some pluses to keeping the surviving Gods around. Strictly speaking, they aren't prisoners or slaves as Gods have a knack for finding out when one of their kind is being abused and reminding the abusers why their ancestors feared the Gods accordingly. But the Gods are. . . encouraged, shall we say, to keep quiet about their natures and to stay out of human affairs.
Weight: 312 libs
Age: Unknown, but claims to be the son of one of the original Gods and to be about 4,000 years old. Evidence suggests that he is indeed at least 2,200 years old.
Real Name: Tyr, Son of Odin. Norse God of Justice, War, Soldiers, The Maimed, and the Hanged.
Physical Description: Tyr has trained his body for combat over the course of centuries and it shows. He probably couldn't keep any visible body fat on it if he tried at this point. Legend says his hair is so blond as to be white, but he's been keeping it shaved for centuries. Appears to be a caucasian male over 6-and-a-half feet tall and powerfully built, but with speed in mind. Almost like it was done on purpose, his build is about as muscular as one can get without sacrificing speed and agility. Worth noting is that his left hand at some point seems to have been replaced with a magical prosthetic, he claims he lost it in battle with the demon-wolf Fenrir. As for clothing, he prefers function to form by a long shot- but usually can be found with at least a Desert Eagle 44, a few grenades, and a melee weapon of some kind usually a spear and a shield- but all are picked more for the mission at hand then anything.
Origin: If what he claims is true, the Tyr was born 4,000 years ago. His father was Odin, one of the original gods, and his mother was either Odin's wife the Goddess Freya, or one of the giantesses Grid or Saga. Given his stature, probably the Goddess. 6'7" was a giant of a man in those times, but in terms of Gods he was a bit of a runt as Gods go. Especially when it was discovered that while he had Godly psychic potential he hadn't seemed to develop any outlet for this potential. He would train his body in combat and warfare all the harder to compensate.
Of course, the runt suddenly became a prize when they figured out that Tyr just had no outward outlet for his psychic potential- his powers turned inward. Honing his mind, body, and will into one solid weapon, Tyr would soundly upset his brother Thor for the much coveted title of God of War. The two brothers developed a friendly rivalry after that, collecting titles. Thor would eventually be God of Thunder, Lightning, Strength, and the Storms but Tyr would at first stood proud as God of War and Soldiers. His last three titles would come from a group of villages that were sacked by Frost Giants while the menfolk were out waging a war in his name. He would use his skills and power to avenge the brutal atrocity, earning his three other titles as God of Justice, the Maimed, and the Hanged.
Most Gods become disconnected from Humanity, Tyr never did to that level. He was above it, a God among Men sure- but that didn't make their pain any less real then his own. The runt would side with the Humans in most things- a God who forsook the lofty and fancy gilded halls of the God-City of Asgard to protect the human race. When the God-Revolution and the End of the Age of Mythology came for the Asgardians, Tyr stood for whichever side was more Just in any given battle no matter whom was involved- he's fight with the Humans when against Gods like Loki or Hel and with his follow, if less then completely dedicated, protector of humanity Thor when they came for him.
Asgard didn't so much fall as hide itself deep under Norwegian Ice as a result. A place where the Gods would be hidden away, and the world became a world of Men. Tyr would hardly notice, he agreed to at least try to keep his identity a secret for the uninitiated in order to continue his work of standing for the weak and helpless against those who would threaten them. Mostly against supernatural threats, granted- but he's been there. "Quietly" working in the background. A wanderer who went where he thought he was needed, he still wanders to this day- though he has come to the US often. He finds the ideals it was founded on intriguing, though he finds it falls short of these ideals often. Not everyone is a God of a higher standard after all.
Powers: Tyr is an 'immortal' God and proud of it. Don't be mistaken, it is possible for Tyr to die. It's just not easy. He does not age, does not get poisoned, does not get sick, he heals quickly, and isn't that easy to wound in the first place. Like all Gods Tyr's strength, speed, agility, and stamina are all clearly in the superhuman range. There are better in all categories, but he's superhuman in all of them. By Godly standards Tyr is very high in all of these categories but not to a point it's impossible for them to reach. His brother Thor is stronger for instance. An analogy that comes up often is that he's to the Gods what Bruce Lee was to Humans. It's worth noting that he may be above Mortals physically, Supermortals is a different standard altogether.
Tyr has thousands of years of experience in combat, against opponents mundane and supernatural, and he's made a point of keeping up to date on developments in Warfare. Between this and his extensive training he's as comfortable using fists and feet as he is using swords and shields as he is using 50-caliber mounted weapons on humvees.
Tyr's left hand is a magical prosthetic, and is noted to be able for form shields and simple weapons made from what seems to be magical energy.