Altarranis is a rather special plane. It was actually formed when a few 'altars' were banished by five Gods that sought to remove the power source which fed a set of Titans who plagued a realm that once existed in Therratallen, the First Plane.
Both the realm and Titans were destroyed in the process, yet all of the matter from that realm was transported into a new plane by the Gods that sought to save the rest of Therratallen from the beastly entities.
Everyone was killed, save for five groups of mortals, each with a Patron God who saved their army from the blast. Yet…the Gods could not destroy 'The Altar of Nimera'—-a literal 'wooden' piece of the Blackroot that turned to stone when it broke free from the dead realm and settled in the core of Thallon, alongside many other altars of the same material that fell along the surface.
Thallon essentially has an infinite set of energy sources, as the Altars drastically changed the resources and magic that pulse through it—-it is therefore known as "The Anointed Realm" because it technically is filled with Gods, powerful mortals, and the Altar of Nimera. It is a tumultuous land, where man-made technology and magic have become one (called magetech, or magan) and the five longstanding kingdoms engage in a never ending cycle of war.
Nimera and the altars have, in many ways, corrupted the Gods that reside in Thallon, or at the very least changed them. There's constant war all over the place as each kingdom vies for power in the name of their Gods—-carrying on their vendettas as old as the plane of Altarranis itself.
Thallonites are incredibly technologically advanced. Weaponry and magetech are developed by mortals through the clever use of industriousness, machinery, magic, and occasionally reverse-engineering deified artifacts from Gods and Titans alike. Warfare is incredibly advanced compared to other planes, but it is also more devastating. The toll it takes on the inhabitants of Thallon are rather substantial.
The five kingdoms are each sprawling landscapes of various machinery, war engines, siege engines, and massive towering structures only made possible by the sheer amount of magic flowing through the realm.
A word of caution when dealing with Thallonites: Do not grab where your hand cannot reach.