Superman is perhaps the hardest character to deal with in a reboot precisely because he needs to be the most stable. He is the yardstick of not only the DC universe, but superheroes in general. Everybody knows who Superman is - he's a saint of popular culture next to Mickey Mouse and Bugs Bunny.
And people don't like it when you mess with their saints.
So the common way to tell an "interesting" (aka post-modern or meta of whatever) Superman story has been to create some analog or alternate Superman. And there is a brickton of those dudes. We have the DC "What If?" Supermen (Soviet, All-Star, Earth-2, Ultraman, etc), rival company Supermen (Captain Marvel, Hyperion, Sentinel, The Samaritan, Omniman, Invincible, Irredeemable, etc), and even super-spoofs (That Will Smith movie, AMIRITE?).
This practice completely suck the opportunity for good Superman stories out of the character. How cool Morrison's All-Star Superman would have been in main DC continuity? (Answer: It would have been tragic-cool) Clearly writers want to write Superman stories, but they (and the publishers) feel that anything too weird would be too damaging to such a core character. Of course, then the publishers turn around and make him a blue electric guy or part robot so what the hell do I know.
Anyways, for the Drewniverse (ha), we'll be keeping Superman in his sacred role. He's the measure. Moreso, he'll be our Alpha and Omega. In our setting, Superman is the first widely known hero. Sure, there were Mystery Men and secret government squads and the like Before Superman (BS), but it was a photo of Superman, hefting a car above his head, that introduced the world to the superheroic age.
But in keeping with not getting too wrapped up in pre-Issue #1 continuity, we'll keep that exact timeframe vague. It was 10-15 years ago that young photographer Jimmy Olson got the snap. Keeping with the measure, we'll use that vague period as a unit of time, the Superman Unit (SU), for describing other character reboots.
But enough about that. Who is the Superman we start with? Same guy we've always known. He's somewhere between 30 and 45 in that Hollywood leading man style and has been active as Superman for about a third of his life. He did play at Superboy a bit in Smallville, but nothing we would have heard of - his Superboy adventures would be pretty much in the future as part of the Legion, not vexing Pa Kent with his indestructible bottom. This helps explain how Superman was pretty much immediately able to step into his role as hero - he interned as one in the future. But that's a reboot for a different day.
Superman has been married to Lois Lane for 1/2 a SU. He maintains his day job as Clark Kent, mild-mannered human interest/feature writer for The Daily Planet. There's rumor around the office that Lois made him give up his foreign correspondent position as a condition of marriage, but Jimmy, Cat, Perry, Steve, and the rest can't agree if it's because Lois was worried about Clark's safety gallivanting around warzones or that she didn't want him overshadowing her investigative journalism.
Superman spends most of his time in Metropolis, but does nip off to the Arctic to putter around his Fortress of Solitude. The Fortress has been around for just under a 1/2 SU. It was actually Lois's idea to make sure her husband has a place where he can indulge in his curiosity, tinker around with Kryptonian technology, and generally relax away from the weight of the world. She suggested it after the Noodle Incident that lead to her learning Clark's real identity in the first place. "Maybe you should test your Trans-Dimensional GravInjector away from population centers in the future, honey. Also, I'm not sure how I feel having a beast made of living knives in the basement."
Speaking of identity - Clark is the real person. Superman is the role he takes on to inspire others, but they're the same person. None of this Clark Kent is Superman's condemnation of humanity bullcrap. If Superman wanted to comment about how humanity sucks, he'd just leave the planet. Because for all his powers (and he has all the ones we're used to) and limitless potential, Superman does have a finite resource: his faith in humanity's inherent goodness.
It's this faith that will slowly wind down over the course of this reboot. As Superman was the Alpha of the Drewniverse, so shall he be the Omega. When he loses that faith in humanity, he stops being Superman. How he loses it, I dunno yet. What happens when he does lose it, I'll leave for Future Drew (me, wrapped in tinfoil) to figure out. Does he take over the world? Does he just leave? Does he die? Find out in 10 years.
But that's a ways off. In the meantime, Superman has villains to fight, the main one being Lex Luthor. That inventor turned corporate plutocrat is also the source of many of Superman's lesser enemies - Metallo, Bizarro, Livewire, Parasite, and so on. Keeping it brief here as each of those could be an entry in their own right.
Other reliable rogues are those jerks at InterGang who are supplying superweapons to Metropolis's criminal effort. You can't rob a bank in that town without at least one sonic cannon or phasic chassis and have a hope of getting away. They also have the resources to stage tragic accidents that will draw Superman away from your heist. For a fee, of course. Where do they get those wonderful toys? It is a mystery...
Lastly, there's Brainiac, that universe-wandering, society downloading, planet destroying robot jerk. His appearance was Superman's first big Save The World moment (.7 SU or so ago). It is from Brainiac that Superman found out a lot about his Kryptonian heritage. Before that, kryptonite was just a glowing green rock that messed Supes up. Now he knows it's chunks of his dead homeworld. Brainiac enjoys taunting Superman with what he knows about Krypton, sometimes claiming to be the one who destroyed it, sometimes saying he tried to save it, although the citizens of the Bottle City of Kandor recently rescued from Brainiac's ship say otherwise. Superman is working to restore the city, with the current theory being that he could use the Phantom Zone's weird rules of time and space to re-embiggen them. Once he gets the Phantom Zone Projector working, he'll likely try it out on a Kandorian volunteer, the hero Dru-Zod. (Spoiler: It does not go well.)
As for the rest of Superman's supporting cast, Supergirl has yet to arrive. Superboy is still in his test-tube, but the timer is almost done. He's actually the third in the attempt to clone Superman (the first being Bizarro), but we'll leave that story for another day.
So there's Superman. Pretty vanilla, I know, but looking over this brief, I see at least three big storyhooks and a handful of medium-sized ones, and that's even before we start introducing other superheroes to the world.