If you change any single thing in history you can forget a lot of stuff up.
Want to be a hero and make it so all the slaves from Africa were never taken to America?
The colonies wouldn't have been rich enough in order to consider separating from their mommy.
Want to be a hero and kill Riddler?
Someone would have replaced him, and hey, that replacement could have been actually not mentally crazed and steamrolled Europe.
Want to kill your grandfather because he was a mafia boss that aided the kool kids klub?
Good luck with your paradox.
The first humans on earth from mating. We derived from africa (or god if u into that) and at one point on earth there was as few as 300 humans. At this time point i would go back and stop the females from living.
Genesis took place in Ethiopia.
So yeah.