As we all learned Fenris is the true creator and progenitor of goblinfolks inluding Darkone and Red Cloak. We also know that Fenris wants to "tear down the world" and was very supportive of the current world's destruction. Goblins are his pet project and despite of their previous failures to dominate other races, he's still working on that, including turning goblins into medium sized monsters in this version of the world, making them bigger and better threats against humans. So what is his endgame? He noticed that his medium sized plan was not enough, so he gave up on this world, and already planning a better version of goblinoids he's going to build in the next world. But to do that, he needs to destroy the current world first, or at least destabilize it enough, so snarl would get loose. To do that he needs a pawn, someone who would let loose snarl in his stead, so none of gods would suspect him. For that:

He placed goblins on poor lands intentionally, so they would feel repressed and rise against the system.
He created a special purple skinned goblinoid, Darkone, who thanks to his unusual feats and features rise above other goblinkin and became a leader of their rebellion against the system.
He gave false information about goblinkind's creation process to Darkone, by using his allies Loki, Rat and Tiamat, so Darkone would seek revenge.
He founded IFCC, tasking them with duty of doing anything to destabilize the world, that's why they wants "unnecessary conflict" and that's also why they stopped V when he was trying to stop Roy.
By using his ally Tiamat's prophet he leaked Serini's location to Xykon, giving him locations of the gates. He used the same prophet to manipulate Eugene, Roy, and ABD, direct them into certain locations so they destroy the gates in his stead.