Seriously, I am curious to find out what motives King Sombra into putting the Crystal Empire into a deep state of sadness and melancholy.
 
With Nightmare Moon, she wanted eternal night so ponies would appreciate the night better (and would have devastated all of Equestria in the process). Discord through Equestria into chaos and discorded the mane 6 for his own amusement. Queen Chrysalis wanted to feed her people by bringing great harm onto Equestria, feed on their love and take over.
 
Will we see King Sombra having a sympathetic reason behind his actions? Like will he have a sad backstory, whereas he forsakes all happiness and takes others’ happiness because he isn’t happy, or he sees any emotion like happiness as a sign of chaos and wants to bring order to Equestria? Or will he be a 2-dimensional villain or merely wants to take over the world or see it burn?