Where exactly is Kadath

Question

In Shikkoku no Sharnoth -What a Beautiful Tomorrow-, there are multiple references to a place known as Kadath, in Act 9 - Sharnoth of the Darkest Black there are references to Inganock particularly when Robin Funnel is talking to Howard Phillips that he should consider being a "Runner" and makes reference to a bird she knew who was a runner (obviously referring to Ati's partner David), Howard replies that he's not familiar which the occupation but he had heard that it's a Kadathian occupation.

I know that when Seikyou is referenced it refers to known locations of earth as London, New York, France and Germany are bringing in Seikyou, also in Sekien no Inganock -What a Beautiful People- in the chapter where Gii fights one of the spawn if the Blood Tree Youki, Gii comments that John Doe's name is a Seikyouan name for "no one", that John's belief in God is a Seikyouan faith and in parts of the story refers to stuff as being originated from Seikyou like Sandwitches.

Whenever travel to Kadath is mentioned they always talk about airships however it also uses the same term to mention travel to Germany and Rome is done by airship as well but never described what these airships look like or their capabilities, considering the Engine Technology that's used throughout the series it wouldn't be surprising if these airships could also travel space (Inganock was made to be totally independent using Engines to manufacture food and the Street Knight, Crack Chrome was almost entirely made of Engines, there are also references to Engine Humans much like Moran),

so i am wondering, is Kadath a fictional continent on Earth or is it a separate world and if so is it dimensional or another planet

Answer 1

Kadath is another world loosely based on the Dream-world from a series of HP Lovecraft short stories. It's the world in which Souten no Celenaria, Sekien no Inganock, and Hikari no Valusia take place and the origin of the steam-based technologies seen within the series.

I don't know the specifics as I have not played Celenaria, but from what I understand it's a parallel world that is connected to Earth/Seikyou via a portal in the North Pole, hence only being accessible by airships, and being an apparently dangerous journey.

As for the level of technology, I don't believe they have space travel, but Kadath is where airships were invented, and they do have floating fortresses and other higher technology marvels, especially after the Infinite Mist around Inganock cleared, and the breakthoughs of the Phenomenon Equation Experiment were shared, allowing development of crack engines and other technologies based on the Equation.

Answer 2

Actually, and this is a spoiler

Kadath (in the original story that the city is first mentioned in : The Dreamquest of Unknown Kadath) is actually Boston. This is revealed at the end of the Lovecraft work the above poster is talking about.