The Waking World is not Earth, but it was built from Earth's bones. It is an alternate history in which Constantinople - here called Tsarigrad - became the enduring center of civilization rather than Rome. There is no Roman Empire that swallowed the Mediterranean and defined what "Western" means. Instead, the eastern Basileia and the western Neustria developed as parallel powers until a dynastic marriage merged them into a single kingdom: Valdara. Tsarigrad is its eastern capital, Karlingrad its western capital, and Ikosium - on the Numidian coast - is the holy city where The Faith keeps its heart. There is no other continent. Oikoumene is the only known landmass, and every culture on it exists within reach of the same inland sea.
That single design choice - removing Rome as the organizing principle - opened the door for the rest of the world to share the stage. Modern fantasy overwhelmingly draws from a narrow corridor of English, French, and Norse tradition, not because those are the richest sources, but because Rome's legacy made them the default. By building a world where that default never took hold, Grimmloch gives equal weight to Wendish forest spirits and Numidian highland traditions, to Achaean philosophy and Aryan fire worship, to Skanne sagas and Arzawan djinn. The seventeen allodial regions are not exotic additions to a familiar European core - they are the core, and the kingdom that contains them all is the frame that holds them together.
The Waking World runs parallel to real history closely enough that you can orient yourself without a textbook. If you know roughly where Persia was, you already have a head start on Arya. If you know what the Norse were about, Skania will feel familiar before you read a word. The alternate history is not a puzzle to solve - it is a shortcut that lets you carry what you already know about real-world cultures into the game and spend your energy on the parts that matter: who your character is, what they carry with them, and what happens when they cross through the Gates of Horn and Ivory into the dream.