The map of Khul in Titan - The Fighting Fantasy World suggests that the Hiang-Kiang River flows through the Spider Fens and that you must cross it to pass through them, but in Sword of the Samurai this is not the case.
Dwarfs were already roaming Titan when "man was still swinging about in trees".[9]
"When the world was still forming, many millennia before the first men set foot upon its surface, Khul and Allansia were joined by a narrow land-bridge, which later separated, as the two continents drifted apart, to create a string of islands".[10]
The Inland Sea was formed "aeons ago" by a massive earthquake which dropped the land by several hundred metres.[11]
↑"When the Dark Lords of Chaos were banished from the Earthly Plane and imprisoned in the Void, their generals, the Demon Princes, fled into the darkest corners of what became known as the Demonic Planes, where they quietly rebuilt their strength.." ''Titan - The Fighting Fantasy World, pg. 87