The Hulk, also known as The Incredible Hulk is the main hero of the Hulk Universe - although a creature of rage and destruction Hulk has a human side and this separates him from the more monstrous opponents such as Abomination or the Leader - Hulk is often confused and alone in the world and wants to be left alone yet is forever hounded by heroes and villains alike, this forces Hulk to fight and this only serves to make him angrier and stronger.
Under the monstrous exterior and rampaging Hulk has a gentle side, especially towards Betty - the one woman he truly loves and one of the few friends Hulk truly trusts.
Hulk began life as Bruce Banner and suffered an abusive childhood at the hands of his cruel father, who murdered his mother in front of his eyes and bullied him into silence under threats that he would go to Hell if he did.
Although Bruce managed to escape his father and grow to become a world expert on gamma-radiation his past never truly left and when he was caught up in a freak accident his inner-anxieties gave birth to the Hulk, a creature born of Bruce's rage at the world, yet despite its naturally aggressive nature Hulk often showed restrained (at least by his standards) - suggesting that Bruce had some limited control over the being - though as Hulk became more angered his actions became ever more hard to control.
Bruce would come to see the Hulk as a monster and indeed most of the world viewed him that way to but in reality Hulk was misunderstood, wishing to be left alone and willing to defend the world from truly monstrous opponents despite his mistreatment.
In at least on future, known as Future Imperfect, Hulk is shown to have ultimately lost his battle for humanity and devolved into the dictator known as Maestro - however present Hulk rejected this future and claims he can make things right.. whether Hulk can achieve this or not is unknown but the "Green Giant" has never been one to back away from a fight - especially if the cause is just.