Gehenna Dawn by Jay Allan
Approx. 77,550 words.
Published on November 9, 2013.
Erastus is steaming hot hell world that pushes men to the brink of endurance. But it is also one of the battlefields where man is fighting the alien Tegeri, and Jake Taylor and his brethren are sent there to spend the rest of their lives fighting a relentless and enigmatic foe.
Gehenna Dawn is the first book of Portal Wars, by the author of the best-selling Crimson Worlds series.