Heroshi, the Prime Material Plane

(he*ro*she)Composed of the overlapping elemental planes. Its sky connects with the farthest reaches of Erhad. Its core connects with the deepest reaches of Nuegalon. It has no sun, but rather, is lit during the day by the Sphere of Light in the center of Erhad. At night, the Sphere of Darkness from Nuegalon overlaps into the Prime Material.

Inhabitants: Mankind: Humans, Halflings, Ungiants, Giants, Elves, Dwarves, Gnomes; Monsterkind: Orcs, Trolls, Goblins, Gnolls, Ogres, Harpies; Wildkind: Vanara, Nezumi, Tengu, etc.

Quintessia, the Ethereal Plane

(kwin*tes*sia) This plane coexists with the material plane. The Prime Material plane and each of its alternates has its own. While most areas took like washed out versions of the material plane, places become saturated with color based on the number of living creatures in the vicinity. Cities are bright with vibrant colors, whereas uninhabited areas are dull and gray. Like other undead, ghosts appear solid but devoid of color. The ethereal is a neutral plane with a slight inclination toward law. Formians, Inevitables, and even Modrons are known to inhabit the Ethereal Plane. Meteors float randomly throughout the plane and often serve as the basis for the civilizations of the plane. Gravity is subjective, and things far enough away from the bubble generated by living creatures will slowly drift in whatever direction they're headed.

Inhabitants: Inevitables, Kith, Ghosts, Formians

Seidheim, the Mana Plane

(seed*hime) The plane of mana is a realm of mystical energy. Arcane spellcasters draw energy is from this plane to use as the raw materials for their spells. The mana plane appears formless until minds interact with it, then illusory images form that reflect the viewers perception of magic. Druids tend to see a natural landscape; wizards, a grand library; sorcerers, an environment inhabited by their bloodline; and such.

Inhabitants: Dweomers, Geists, Fey

Umbranimus, the Shadow Plane

(um*bra*ni*mus) This negative realm mirrors Heroshi and connects it to other realms. It's landscape appears to be shifted into the negative spectrum. By day the sky is rusty brown and grass and trees are magenta. Creatures in the Shadow Plane also appear in the negative spectrum, but also has the effect of making them look haggard as long as they are on the plane. The plane is mildly chaotic aligned.

Inhabitants: Senexti, Chaos Beasts

Erhad, the Celestial Plane

(air*hahd) The sky of Erhad merges with Heroshi's sky. In the center of Erhad is the Sphere of Light which is composed of the souls people who died serving good, putting others before themselves and generally assisting and protecting life. The outer regions of Erhad are increasingly more chaotic and the closer to the center the more lawful. The soul sphere is treated essentially as the Positive Energy Plane. Solars inhabit the core, and Stellars and Lunars the outer rim. In Erhad there are planets. One can enter these planets to pass into a demiplane such as the outer planes listed in the DMG, but only the good aligned ones. The lunars are caretakers of the moons of Heroshi, which appear in the sky of the material plane at night.

Inhabitants: Angels, Guardinals, Archons

Nuegalon, the Fiendish Plane

(noo*ey*gah*lawn) In the core of Nuegalon is the heart of darkness, made from the essence of the evil souls (those who put themselves before others and by action or inaction brought innocents to harm) who died on the material plane. The region near the core is intensely chaotic but becomes more lawful the closer to the surface you journey. The core also merges with the core of the material plane. Undead such as nightshades and demons inhabit the core and devils the surface. There are portals in Nuegalon through which one can enter a hellscape such as the evil aligned planes listed in the DMG.

Inhabitants: Demons, Devils, Yugoloths, Undead

Elemental Planes

Earth - Structured like a geode, with outer and inner sufaces and tunnels weaving throughout. It is the source of all minerals and gemstones. It is cool on the ouside and warm on the inside.

Inhabitants: Xorns, Earth Elementals, Mephits (Earth, Salt, Magma), Yumas

Water - Water throughout. On the outside of the sphere the water's surface is a continual maelstrom. It's frozen core  is what causes the cold climate of Heroshi's southern reaches where they overlap.

Inhabitants: Water Elementals, Tritons, Mephits (Water, Ice, and Ooze), Marids

Air - Open sky with clouds throughout. On the inside is the air is cool and bright, populated with stratus and cumulous clouds. The outside is warm, humid, and dark, with rumbling nimbus clouds.

Inhabitants: Arrowhawks, Air Elementals, Djinn, Mephits (Air, Dust, and Steam), Sylphs

Fire - The plane of fire is a globe of magma in the center with rivers of lava radiating from it. Gravity is toward the outside, with the surface on the inside, so the orb of magma beats down from overhead with its heat. This magma orb causes the hot climate at the northern regions of Heroshi.

Inhabitants: Magmin, Fire Elementals, Azer, Efreet, Salamanders, Mephits (Fire, Magma, and Steam)