One Star System
A System with superheroes and supervillains existing in it. Sentient alien species (such as Kryptonians and Martians) are generally known to exist, and the arrival of alien spacecraft is not uncommon. Technologies, such as artificial intelligence and faster-than-light travel, are functional and reproducible, though they are highly experimental and difficult to achieve. Demonstrable magic exists and can be learned.
Prime Earth was formed by the temporal merging of the disparate DC, Vertigo and WildStorm universes, in an effort by Pandora and The Flash to restore the Time-stream to its intended nature.
In this newly made universe, costumed crime fighters are a relatively new phenomenon, with Superman being the first super-powered hero to come to public knowledge. Since then, several other heroes have come to the fore, with the formation of the Justice League. The success of the Justice League activities inspired the United Nations to create the government-sponsored team Justice League International.
Of course, there are also the supervillains, individuals that use their powers to commit evil, as well as N.O.W.H.E.R.E., an organization with a nefarious interest in superhumans and their abilities.
Demonic entities vary from the Demon Etrigan, to Blaze, Satanus and Neron. Demonic entities are abundant and come from Hell although some like Eclipso, the vengeance demon (also referred to as the Prince of Darkness), reside on the Moon. Demonic Entities from Wonder Woman comics are directly linked to Greek Mythology such as Hades, and Ares. In the Vertigo comics, characters like John Constantine oppose demons influenced by Christian mythology. Most Demons are not however directly linked to Demonology.
Book of the Black
Technology more advanced than that which normally exists is available - but it is usually very expensive, and usually only rich or powerful individuals and organizations (or the scientific geniuses who create them) have access to them. S.T.A.R. Labs is an independent research outfit that often develops these devices, while Lexcorp is the main company selling them. It must also be noted that the government also runs the secret Project Cadmus (located in the mountains near Metropolis) to develop clones and genetic manipulation without the public's knowledge. Technology can also come from outer space or different time-lines. Apokolips weaponry is often sold in Metropolis to the criminal organization known as Intergang.
Robots and similar creations, including cyborgs, can have superior intelligence when they are created as sentient beings. The Manhunters, the Metal Men, Red Tornado, Robotman, Hourman, and Metallo are but a few examples. These 'beings' are most often created by individuals who possess vast intellects, like scientists Professor T.O. Morrow (maker of the Red Tornado), Dr. Will Magnus (who constructed the Metal Men) and Professor Ivo (who fabricated Amazo and other advanced androids using a form of Nano-technology developed by Lexcorp). Brainiac also emulates this technology as well as technology from other worlds. Similarly, some characters use technology to enhance their armor or modify cybernetic functions, for example Steel, Cyborg and the Cyborg Superman.
DC Database Prime Earth Article- http://dc.wikia.com/wiki/Prime_Earth
Wikipedia DC Universe Article- http://en.wikipedia.org/wiki/DC_Universe