LJUBLJANA — When one looks for a figure who best represents the worst tendencies of our brutal age, the first names that come to mind include Yahya Sinwar (Hamas’s leader in Gaza), Binyamin Netanyahu, Kim Jong-un, or Vladimir Putin. But that is primarily because we are bombarded with news about these leaders. If we widen the lens to account for horrors that Western mainstream media largely ignore, those waging Sudan’s civil war stand out even more. The country’s new warlords are displaying shocking cruelty and indifference toward their own people (or those living in the regions they control), including by...