The prophecy was that lost powers will awaken and the era of chaos will start. The brother just didn't think that roderick who still hasn't awakened his powers can fight back against melon and russell who have already awakened their powers. Since it was kaien empire who brought down the daimon empire, they're taking revenge + start their empire again. The brother thought he could at least protect the people of kaien this way. And truth be told, if fl wasn't here, roderick wouldn't have lasted long. But that doesn't make what he did right. Roderick even tries to reason with him but he never believed in his own brother.
Yeah..if only he knew we have lee jae and the boy king Arthur ( the OP guardian god, the strongest, the handsomest king whose genes are so strong that even after centuries his descendants still resemble him) on our side. Without these two it really would have been impossible. Ofcourse hailey played an important role. If she hadn't died, lee jae wouldn't be here.
It's not that I don't have empathy, but this time I'm grateful Hailey is dead, so at least their kingdom won't be destroyed because Lee Jae possessed Hailey's real body, but by the way, who is the descendants of the guardian god in this story? Have they appeared yet? Their descendants, I mean? Did I skip that chapter?

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The brother is the cause. He's the one sending all those evil spirits