How about plunge an entire world into darkness? Hasn't happened yet, but...

[He gulps and shudders, a grimace crawling across his face. It probably sounds stupid. Abstract or even unbelievable. Riku was shocked when he first heard, but after everything that's happened here, it's become a bit harder to deny, even if everything turns out right.

Maybe he oughta focus on something a little easier to grasp for now.]

But sometimes people can change. They don't always, but there's always a chance that they can turn things around. They just have to be willing to try.