Originally I was thinking Noxus was the most evil place in LoL, since they want to conquer land. But's only half true, they don't wanna conquer land cause they are bloodthirsty murderous, they do it cause their land is made of rock and iron, no farm land and barely any trading materials.
And when I saw that comic made about Darius, I was instantly thinking "they are way to nice to thief children and way to friendly to other villages".
All they do is asking for help by other countries to help them achieve their goals, if they threaten Noxus, they bring arms and makes examples of those who deny them, doe they doesn't really make war with anyone except those who want war (Demacia and Inoia).
Piltover and Zaun is left untouched on the radar cause they are the only trading centers. Noxus don't care about cities, since they only want farm land.
Demacia on the other hand has a whole lot of stupid rules, strict punishments to those who break them, and their reason to fight Noxus is just plain revenge for their king (who was killed by Sion).
We can count Shadowisles as the most evil country, but honestly. It's only the outsiders like Mordekazer, Hecarim and Elise that makes Shadow isles, evil.
There's thresh too which I totally count as the Most evil guy in all of LoL. But one guy doesn't really count. It's almost just as J4's father and Cassopiea.
If we count all the good guys in Shadowisles, who try to keep the humans and nature safe. Moakai, Kalista and Yorick. I don't see the isles as any bad at all.
I probobly need more theories to back this up. But Honestly just like Solaris and Lunaris, it's the once who act like "good guys" who are the "bad guys".
Edit: Wooo Thx for all the responses, makes me understand this world much more. I kinda love Swain's concept and how similar he sounds like my life :D I wanna be a politic leader too someday.. Maybe even shave my forehead and grow a backhair :3