Myriad Realms Online is set in a vast and magical world made up of nine different realms, each with its own unique characteristics and inhabitants.

The first realm is the Realm of the Celestials, a bright and peaceful realm filled with angels, unicorns, and other celestial beings. This realm is divided into three continents: Elysium, the land of eternal happiness; Celestia, the land of the gods; and Solaria, the land of the sun. The Celestials are a highly advanced civilization, with a strong emphasis on spirituality and the pursuit of knowledge. The most powerful kingdom in this realm is the Kingdom of the Heavens, ruled by the wise and benevolent King Solomon.

The second realm is the Realm of the Demons, a dark and chaotic realm ruled by powerful demon lords. This realm is divided into three continents: Infernum, the land of eternal fire; Gehenna, the land of the damned; and Avernus, the land of the abyss. The Demons are a brutal and savage people, constantly at war with each other and with the other realms. The most powerful empire in this realm is the Empire of the Fallen, ruled by the fearsome Emperor Lucifer.

The third realm is the Realm of the Dragons, a realm filled with majestic dragon clans and ruled by the powerful Dragon King. This realm is divided into three continents: Draconia, the land of the dragons; Wyrmwood, the land of the wyverns; and Drakemount, the land of the drakes. The Dragons are a noble and honorable people, but they are also fiercely territorial and will defend their lands at all costs. The most powerful clan in this realm is the Clan of the Five Dragons, led by the Dragon King himself.

The fourth realm is the Realm of the Fairies, a realm of beauty and magic filled with all manner of magical creatures. This realm is divided into three continents: Faerie Glen, the land of the sprites; Enchanted Forest, the land of the dryads; and Pixie Valley, the land of the pixies. The Fairies are a playful and mischievous people, known for their love of pranks and trickery. The most powerful kingdom in this realm is the Kingdom of the Faeries, ruled by the beautiful and cunning Queen Titania.

The fifth realm is the Realm of the Undead, a realm of death and decay ruled by powerful necromancers. This realm is divided into three continents: Necropolis, the land of the dead; Crypt, the land of the vampires; and Wraithwood, the land of the ghosts. The Undead are a sinister and manipulative people, constantly scheming and plotting against each other and the other realms. The most powerful empire in this realm is the Empire of the Lich King, ruled by the feared and powerful Lich King himself.

The sixth realm is the Realm of the Beasts, a realm of savagery and primal instinct ruled by powerful beast clans. This realm is divided into three continents: Wildlands, the land of the wolves; Savage Isle, the land of the barbarians; and Dragon's Maw, the land of the dragons. The Beasts are a brutal and savage people, living only for battle and conquest. The most powerful clan in this realm is the Clan of the Five Beasts, led by the mighty Wolf King.

The seventh realm is the Realm of the Humans, a realm of mortals and technology ruled by powerful human empires. This realm is divided into three continents: The Old World, the land of the ancient empires; The New World, the land of the colonial powers; and The Future World, the land of the cybernetic revolution. The Humans are a diverse and adaptable people, constantly striving to improve their lives and advance their civilizations. The most powerful empire in this realm is the Empire of the Rising Sun, a technologically advanced and expansionist empire ruled by the ambitious Emperor Hirohito.

The eighth realm is the Realm of the Elementals, a realm of raw elemental magic ruled by powerful elemental lords. This realm is divided into three continents: The Firelands, the land of the fire elementals; The Waterlands, the land of the water elementals; and The Earthlands, the land of the earth elementals. The Elementals are a proud and honorable people, fiercely loyal to their respective elemental lords. The most powerful kingdom in this realm is the Kingdom of the Four Elements, ruled by the powerful and wise Elemental King.

The ninth and final realm is the Realm of the Gods, a realm of pure divine power ruled by the powerful gods and goddesses of the pantheons. This realm is divided into three continents: Olympus, the land of the Greek gods; Asgard, the land of the Norse gods; and Mount Celestia, the land of the Celestial gods. The Gods are a proud and haughty people, constantly scheming and fighting against each other for supremacy. The most powerful pantheon in this realm is the Pantheon of the Overlord, ruled by the mighty and all-powerful Zeus.

These nine realms are connected by portals that allow players to travel between them.