The twist when you beat the game is that you're the evil overlord all along, and you are enslaving those survivors you "rescue". The overlord was in fact trying to provide sanctuary from you, while using the robots as guards. That's why he never attacks, but you do.
"Divide to Reign".
The Overlord is actually a nice guy. He's just acting as an Overlord to force survivors to cooperate. If he wasn't there, every time shard would be raiding each other, killing the women and raping the warriors. Or the other way around.
By pretending to be evil and stuff, the Overlord is in fact the nicest guy in the game, sacrificing his own life to became "that thing we don't want to see again", while turning glyphs bearers into heroes.
The truth is that, in fact, the Overlord is following the Ilari's orders. The Ilaris' secret plan to enslave mankind is using glyphs bearers as "host". First, they created the Calamity, then they created an Enemy, and then they created Heroes. And when the overlord is defeated, the Hero become an Overseer, leading the settlements, and then the Ilari ASSUMES DIRECT CONTROL and start leading mankind.
A Valley Without Wind is just about you helping the Ilaris to control mankind by destroying the Overlord. And if you decide to fight against the Ilaris instead of helping them to achieve their nefarious schemes, well, accidents happen...
If you don't understand, let me explain again:The Ilaris are evil 'n' stuff. They created the Calamity, for the lulz. Their next goal is to start oppressing humans, through replaceable leaders. That way, if humans rebels and get rid of their current leader, they can put another one instead to replace the overthrown one.
But in order to unite all the survivors from the differents time shards, they first created the wind, to force the survivors to live together, and then they created the Overlord, to give survivors a reason to stick together. After all, when you know there's an evil guy running around, you don't say "screw you guys I'm going home". Unless you're in a horror movie.
The plan is: once the glyph bearer get rid of the Overlord, the Ilaris will possess the hero, while officially retreat to a higher plane of existence or whatever. Then the human host will start repress the survivors. If he's overthrown, the Ilaris will say something like "ur next boss will born in a stable" or something, but the same thing will happen again and again.
And if your character dies, it's obviously because the Ilaris conspired to kill him.
In other words, my characters are all genius, because they keep dying, and it's never my fault!