Pendulum

Eric Albright was a luckless journalist living a so-so life...until the day he opened a battered red door under a railway bridge and entered Levaal, a magical world between worlds. A place populated by power-damaged mages, stone giants, pit devils-and dragons. The tyrant Lord Vous rules with an iron fist and is nearing his goal of turning himself into a god. He's kept at bay only by the great Wall at World's End, which contains all of Levaal. But, the Wall comes crashing down, sparking a violent war, and Eric and his friends are caught in the thick of it. They are forced to flee from the Tormentors, dreadful creatures that have poured through the breach, and there are rumors that one of the great dragons has escaped its sky prison. Worse yet, Vous's journey to godhood is almost complete, and a mysterious being called Shadow-who is not but looks remarkably like Eric-is wandering Levaal with great power but no purpose it yet understands. The end might be coming faster than anyone thinks.

When Eric Albright, a luckless London slacker, and his pal Stuart Casey went through a battered red door under a railway bridge, the last thing they expected to find was another world. There lay the strange, dark realm of Levaal, whose tyrant lord Vous has ascended to godhood. The great wall, which has divided the land has been brought down, setting loose a horde of demonic Tormentors. In their sky prisons, the dragons are stirring, set to defy their slumbering creator and steal humanity's world. Shilen, a dragon cloaked in human form, has convinced Eric and Aziel, Vous's daughter, to help free the dragons from their sky-prison, or Earth will be destroyed. She promises great power, and safety for all Eric's favoured people, but Shilen has an ulterior motive, for the dragons wish to control humankind completely.