It is a battle of the 3 smartest people in their worlds! They want to conquer the entire world under their regime! Who will ultimately come out on top?
Lelouch is born into royality, has his Geass, will ultimately acquire his mobile suit and full use of his powers
Lex has his wealth and resources and does not have superman to thwart his plans. He will ultimately end up acquiring his power-suit.
Dr Doom is born into wealth but have none of his magical powers, furthermore he does not have a time machine and he cannot steal powers from anyone. He does however have his suit and it is in a world without Reed Richards thwarting his plans.
They are all born at the same time with an immovable motive to conquer the entire world by being it's sole dictator and leader. Lelouch striving to achieve the peace he acquires in his final episode, Lex wanting to better the world like in the Red Son, and Dr Doom wanting to achieve the one and only perfect timeline as he explained it to the Panther God.
There are no aliens in this world nor are there gods or superheroes with super powers. All technologies from the 3 worlds are available up for grabs.
Lelouch is born in Asia
Lex Luthor in America.
Dr Doom in Europe.
Who will end up ultimately controlling the world? Who will survive?
Bonus: and to add a chaotic and unpredictable element.
It is in a world where L lives and he has access to his Deathnote. L's moral compass is on and will kill anyone he deems evil.
EDIT: Before everyone rushes to say Doom. Remember that this is a game of subtlety and year long strategy not a quick tactic to entrap people. Come out too early as a contender and the other players will be aware of your presence. Come out too dominating and evil and then you get killed by L.
Lex and Doom can't build a grand deux ex machina weapon that would enslave people without the rest of the population knowing. This only way to win is through command, conquer and politics. Of course, powerful weapons are still in play like the knightmares etc.