Gamble

Gamble was a vastly powerful Marvel comics supervillain from the now cancelled Marvel UK title - like many Marvel UK villains he is exceptionally powerful, indeed Gamble is especially potent and may very well be one of the most powerful beings in the Marvel universe (at least within his scope of influence).

Claiming to be a member of a race of unimaginably ancient beings born soon after sentience came into existence, at first they existed on a subconscious level but as soon as the first species dreamed they came into physical being and began to feed on dreams.

These beings would create the Dreamscape to further their feeding habits as well as a source of amusement - naming themselves Dreamscapers.

However as is inevitable with all evil species the Dreamscapers began to fragment as the multiverse rebelled against them and soon the Dreamscapers became lost from one another, scattered across infinite worlds.

Gamble believed himself to be the last functioning Dreamscaper and entered the Marvel UK dimension, where he took a planet and converted it into his own "Gamesworld" where he ruled as a mad trap master - capturing hapless individuals and forcing them to fight other prisoners in the playground-like maze, the losers were killed or kept as playthings by Gamble until he grew bored of them, at which point he discarded them like trash.

Eventually Gamble grew bored and sought his sights on larger plans, beginning with tormenting the hero known as Adam Warlock..

Trivia

 * Gamble is a very confusing character that blends elements of the Beyonder, Nightmare and Arcade into one man - it is possible that Gamble is related to Nightmare and Cobweb (who may be Dreamscapers) : much like Nightmare and Cobweb Gamble's omnipotent power is mostly within the Dreamscape and he is more limited outside that realm.
 * Gamble stated he was more powerful than Galactus, this is true - within the Dreamscape Gamble is absolutely omnipotent (much as a Hell Lord like Mephisto is completely omnipotent within their native realm) : outside the Dreamscape however Gamble is not a match for Galactus.