If you have not played either Darksiders games, you might want to skip this one some pretty major spoilers ahead, but then I guess if you're reading this it's because you have played them and want Darksiders 3.
At the end of Darksiders War is banished due to him breaking the rules, he went to Earth without the proper authorization, however, he was tricked into thinking the signs were real. This is where Darksiders 2 starts, Death wants to clear his brother's name, to do this he needs to turn back time. There is one pretty major catch, Death must sacrifice himself or the souls of the Nephilim to turn back time.
And this is where the cliffhanger arrives, what happens to Death? What happens to War? I don't want to speculate about story lines because Vigil Games are far better at that than I. But that doesn't stop the fact that a great series has not be closed, and it deserves to be ended.