Many cultures have the concept of a punisher, or an 'adversary'. Most religions embrace the concept that cruel or hateful people will be punished.
There have been many entities who claim the role of Satan, such as Chthon, an ancient First God. Another one, a dark New God named Mephisto, rules over his own dark dimension and styles himself as a Shai'tan to bargain power and lure the cruel and the wicked to him. He offers power and gifts to people willing to grant him their souls-- but he is not the ruler of Hell. He is merely in possession of a realm close to Hell, over which he has absolute rule.
The concept of a place of eternal suffering resonates with all cultures, each with vague or specific ideas of what this 'hell' would be. If there is one constant among the universe, it is is that Hell is on the road to nowhere, but all roads potentially lead to Hell. Hell-- the true Hell-- is the lowest of low places. No other dimension is furthur from the seat of Creation. No other realm attracts the cruelest and most destructive of spirits. It is a place where narcissists and dictators find themselves, in the company of all others who believe that dominion over others is the only virtue, and the base memory of the existence of Hell is common to all mortal races.
Despite many dimensions that style themselves as Hell, there is only one that exists in the base race memory of all sentient beings. This is the Hell of collected legend-- a place where the wicked and cruel find their soul deposited.
It was not created as a torturous realm, but rather it was warped by the spirit of the first entity to occupy it. Lucifer Morningstar, the Dawnbringer, the Left Hand of God, was the original rebel. His rebellion against Heaven was struck down and Lucifer fled as far from his failure as he could. Hell changed around him, reflecting the Fallen's anger and his loneliness.
As other entities found Hell and occupied the land, it began reflecting their visions and personality as well. Some were members of the failed resistance led by Lucifer-- Asmodel, Lillith, and Xaphan, among others; angels of light and grace turned to hate and malice. From their presence, Hell changed more, reflecting the cruelty of tyranny. It became a place for narcissists and those who seek dominion over others. This suffering attracted demons, creatures of the Astral Plane drawn to locations of intense psychic presence.
Blood from their wounds dripped on the ground, and from it sprouted up Hellions, creatures that bickered and fought for power and position. The mightiest of them became Hell Lords, ruling over a specific domain of Hell, their power matched by the number of souls attuned to their portfolio. Hell Lords spend their timeless eternity jockeying with one another for the scraps of power the others possess, and showing fawning subservience to the Fallen, when not plotting to overthrow them. The only real power in Hell is subjugation of others, and Hell Lords exemplify this ideal in their dealings with one another.
Hell is ruthlessly egalitarian. A hierarchy of knights, nobility, lords, and areas of responsibility exists. Whenever Mortals dwell together in life, a Hell Lord rules over an infernal echo of that realm. As a city descends into chaos and depravity, the Hell Lord's power grows. Petitioners-- mortals who choose to embrace Hell's cruelty-- form the lowest of ranks, alongside the demonic slaves and monsters that grow like wild fungii out of the blasted dirt. Given long enough, petitioners start to be changed by Hell's influence, becoming demons in their own right.
No one is actually ever sent to 'hell'. Someone greedy in life finds himself drawn to the infernal echo of the city he lived in; someone given to sadism might be drawn to a Hell Lord who rules over the cruel. Hell is a horrific place, but it is not a place intended to inflict punishment. The real punishment is self-inflicted; the blackened, tortured souls who come to occupy Hell do so because they fit nowhere else in Creation. Some seek absolution or penance, but the worst of them seek only domination.