Freddie Sykes began life as a common criminal who had taken to reading fairy tales whilst in prison - much to the dismay of the unfortunate inmate who shared his cell, Sykes was more than a little obsessed with the subject and was especially fascinated by the Arabian Nights and its tales about the mythological genies.
After being released Freddie somehow managed to travel the world as an archeologist - uncovering ancient treasures, as fate would have it one of the treasures Freddie stumbled across was a mystical bottle that contained a powerful wish-granting genie right out of the fairy tales Freddie spent hours reading whilst in prison.
At once amazed by the discovery of a real genie Freddie's greed soon surfaced when, upon hearing that the genie would grant him any wish he desired for all of eternity, he instantly took advantage of the situation and ordered the genie to build him a castle made out of solid gold.
The genie did so without question and soon Freddie was in possession of a modern wonder of the world, yet even this grand building was not enough for Freddie as he declared to the genie he wanted more.. a LOT more..
Reign of Terror
Freddie goes completely insane with power and orders his hapless genie to grant his every wish - which begin to grow more and more megalomaniacal with each passing moment: Freddie orders the genie to grant him a flying horse, many other extragavant "gifts" and even forces the genie to rewrite history by having Nixon become victorious in '68 (ironically the real Nixon was voted in just a year later).
Freddie then decides to push his gift to the limits and orders the horrified genie to block out the entire sun - casting the world into a panic as entire nations feared the extinction of the human race or some kind of Biblical prophecy, since they had no idea what was happening around themselves.
A God Am I
By this point even the genie himself knows that Freddie is not only a criminal but completely insane, however he is powerless to stop Freddie as the madman decides to make his ultimate wish - to become a genie himself by switching places with the genie who had served him.
Left with no choice the genie granted Freddie's wish and was transformed into a human, the now all-powerful Freddie towered over his former genie and mocked him - deciding that he was now a god and could do anything he wanted, starting with destroying his former ally.
Yet as the giant Freddie prepared to crush his victim the former genie ordered him to stop, a confused Freddie found himself unable to resist the command - finding to his horror that as a genie he was now forced to obey the commands of his "master".
The genie-turned-human then acts quickly, ordering Freddie to return to the bottle - sealing the evil would-be-god away and leaving him alone, hoping that by the time someone discovered him Freddie will have learnt his lesson about abusing power..
Freddie Sykes was originally a common criminal (a con-man to be precise) - though he obviously had criminal tendencies he was not shown to be a particularly violent or dangerous individual: however he was already seen as eccentric due to his obsession with fairy tales - his especially strong interest in genies from the Arabian Nights suggests Freddie was also somewhat of a megalomaniac even before his encounter with the genie, since such individuals would be attracted towards stories of such powerful and enigmatic beings.
Upon discovering the genie Freddie became an outright Malignant Narcissist who saw the entire world as little more than his personal plaything - he abused his own genie, treating him as little more than a slave and demanding more and more power as well as extragavant displays of wealth and power, this is the classic behavior of a megalomaniac.
Freddie ultimately developed a desire to become a god and succeeded, yet his malicious glee at becoming all-powerful soon gave way to geniune terror when he realized his new form was also a prison (mostly of his own making).
Powers / Abilities
Prior to his encounter with the genie Freddie had no superhuman or mystical abilities, though he was apparently well-read and no doubt knowledgable on the topics he obsessed over for so long (namely fairy tales), he was also presumably an intelligent man since he was able to enter an archeological expedition after being set free from prison (though whether it was an offical expedition or simply himself is unknown).
After discovering the genie Freddie was granted the ability to rewrite reality as he saw fit, a power he quickly abused as he warped most of Earth into his personal playground.
Upon wishing himself into a genie Freddie gained unlimited power, presumably on a cosmic-scale, yet his omnipotence came at a terrible price as he could no longer do anything without the command of a master (just like genies of folklore).