The Darksiders series isn't really dead. Nordic games owns it, and will presumably do something with it. But the series as we knew it, developed by Vigil Games, may as well have died earlier this year when Vigil went off and joined Crytek and left Darksiders behind, where no major publisher on Earth wanted anything to do with it.
So we'll never get the game that was originally intended to follow Darksiders III. Which is a shame, because it sounds like it might actually have delivered on some of the teases made at the end of the first Darksiders (the only part of that game I really enjoyed), and which went unanswered in the sequel.
Speaking with IGN, Vigil's former creative director Joe Madureira “It was always our hope to do a full four-player co-op game, with all four Horsemen playable. It’s possible we could have pulled it off. I would have liked to introduce Fury and Strife. I know many fans feel robbed that they never got to play the last two Horsemen."
As for story ideas, he says "Story wise, we tossed around the idea of the Horsemen attacking Hell to challenge Lucifer," he continued. "And then taking the battle to the Charred Council to regain their freedom. Epic stuff. There was also an idea to do crazy ‘western’ type story, where the Horsemen are mortals after the rebirth of Mankind, sort of an alternate future. But neither idea got very far.”
And now never will.