Which is it?
Famine, Death, War, Conquest.
There was no order to which these could come.
No matter what cycle you begin with, it will always end in despair.
For example, you could start with Death. Excess death could lead to separation.
So many things can happen when people are truly desperate.
Then, you can come in with famine, making them so hungry, they turn into monsters.
Then, war breaks out, with the emergence of the Horseman of war.
People fight for food and all sorts of perks.
Then, the horseman of conquest comes, plunging the world as theirs.
Will you sell your soul to the devil for a prince to dine at their table?
During that time when everything is dark, you best believe a majority of humans would turn dark too.
And by the time the real war begins, humanity is so divided that it cannot operate well enough to defend itself against the enemy.