>Carcosa orbits two black stars
>Commorragh has two captive black suns
>Carcosa is a city with towers that rise BEHIND the moon
>Commorragh also has mind bending monoliths and towers that do not behave as normal euclidean or non-euclidean structures
>Carcosa (in Pathfinder) is constantly expanding and consuming other realms and adding to itself
>Commorragh also expands and takes over other dimensional realms
>Carcosa is a giant city
>Commorragh is a giant city
>The ruler of Carcosa is a the King in Yellow, a being no normal person can withstand seeing
>The ruler of Commorragh is Asdrubael Vect, a being we normal beings and fans of 40k have not seen any art for but the one picture from before their total faction redesign

Surely this was a conscious decision by someone at GW and not all concidences