It doesn’t even matter if Durza didn’t do the blast to kill people, he is still a villain because he didn’t care that what he did was harming people.
key word “innocent”
He is still a villain for this, because from Y1018-Y1046, he was studying magic and likely knew the catastrophic effects that his magic could create.
“the dark wizard knows nearly all of the secrets to magic”
He didn’t care at all, he just wanted to live. He never showed any remorse after the attack, either.
Durza wanted to rule the world. How are you going to do that without becoming a villain in the process, if you’re not already?
And “destroying a few young wizards’ minds, causing them to go insane” isn’t villain-like behavior? And he didn’t even show remorse or look for a way to undo it. It’s worded like he did it purposefully. And then he raised Ramses II, who would kill people on sight.
Are you sure that destroying continent and risking your own life to be a part of those 80% cuz you was in epicenter of the explosion is considered to be “just to save yourself”? I guess Durza didn’t knew how strong he is, when he used all his power to make that blast.
When he is destroyed the world for the first time, he is lost a lot of opportunities of becoming stronger, so it is not reasonable for him to do that intendenly.