The Lance of Marduk
The Inner Planes
The Inner Planes are what separate the Central Realms of Midgard, The Feywild, The Shadowfell, The Outlands, and Limbo form the Upper Planes of the Astral Sea and the Lower Planes of the Elemental Chaos. These Inner Planes are often confused with the Elemental Chaos, and this is likely from the fact that they are in fact an extension of those Primal Elemental Regions. The Inner Planes have no Gods residing within them mostly home to many of the classic elemental species without being twisted by the Fiendish nature of the Lower Planes of the Elemental Chaos. There are also Elemental Planes of Air, Earth, Water, and Fire; which are teaming with various kinds of creatures including Yugoloths, Elementals, Djinn, Aarakocra, and many others.
The Plane of Air
The Elemental Plane of Air is a whimsical region which is aloft with floating islands, kingdoms, and continents. It is the home of the Djinn who have been looking to escape the wrath of the Planes above and the Planes Below. It has several subregions like Mistral Reach, Sirocco Straits, and the Labyrinth Winds. On the Border with the Plane of Water there is Frostfell, and on the Border with the Plane of Fire is the Great Conflagration
The Plane of Water
An Endless Ocean, the Plane of Water bears more similarity to the Astral Sea than the Elemental Chaos, which also may point to its more Celestial Residents. The Famed Isle of Dread is found here, along with the Sea of Ice (on the border of Frostfell), the Sea of Worlds, and the Silt Flats. The Plane of Water is home to many celestial, aberrant, and natural marine creatures. Bordering the Plane of Earth is the Swamp of Oblivion.
The Plane of Earth
Beyond the Swamp of Oblivion, the Plane of Earth is a mountainous region of great crags and peaks. The Mud Hills and the great Furnaces can be found in this Plane, same as the City of Jewels, one of the most famed locations in the Plane of Earth. On its Border with the Plain of Fire are the Fountains of Creation, a Hadean looking plane of creation which resembles the ancient Earth.
The Plane of Fire
The Famed Plane of Fire is the most like the Elemental Chaos which hath spawned these cursed lands. Beyond the volcanic Fountains of Creation there is the Cinder Waste, a long dead desert born of some great catastrophe. The City of Brass sits on the Edge of the Sea of Fire and is the one location in the Elemental Planes most often met by Mortals.
The Planes of Positive and Negative Energy
Lands which have come to be known as the Planes of Shadow and the Ethereal Realms, the Planes of Positive and Negative Energy. They have become almost forgotten by the scholars of the Mortal Planes, though some of the most ancient texts do speak of their existence, though no mortal has visited them since the Dawn Age.