From publisher blurb: In a world of magic and steam, there are stranger things still! Magic and technology are pervasive and well-understood forces in the world of Aden, at least for the most part. However, there are still forms of magic that few understand and even fewer practice. Entomancy, the magical discipline of the nation of Kyan, emphasizes the summoning and controlling of insects, both in vast swarms and massive individual creatures that do the bidding of their masters. But recently in Aden, a new kind of magic has begun to appear. People with the innate ability to tap into vast, previously undiscovered reservoirs of magic that grant them incredible power have begun to make their presence known and taken the war against the Darkfall to a whole new level. They are known by many names, but the most common is that of Channeler. Challengers of the Impossible is the fifth and final installment in a series of sourcebooks that more closely examines the base classes of the Thunderscape: the World of Aden campaign setting! In this installment, you will find extensive support for the always-bizarre Entomancer class, as well as an entirely new class, the arcane powerhouses known as the Channelers!