Noxus

Additionally to the info on Universe, we know:
 * Noxus' capital was once the immortal bastion, reigned by Mordekaiser.[1]

The last three come from in game loading screen tips.
 * "Basilisks of the Kumungu are sometimes raised from eggs as Noxian war beasts."
 * "Drakehounds, a distant relative of dragons, are kept by some rich, and perhaps foolish, Noxians as pets."
 * "Warmasons are tasked by Noxus not only to plot and plan infrastructure, but also to scout out enemy territory for future invasions."