Books like Crimson Worlds Collection II

The First Imperium (Crimson Worlds IV) The Alliance and its colonies have called a truce and signed the Confederation Agreement, providing the frontier worlds with guarantees of self-government. No one expects the deal to last, and both sides are preparing for the next showdown. But from the depths of space another challenge is coming, one that will endanger the very survival of mankind and force not just the Alliance and its colonies, but all of the Superpowers, to join forces or face annihilation. The dusty ruins the Alliance discovered on Epsilon Eridani IV were built by an ancient race, eons dead. But their guardians remain, and the disturbance of long silent caves triggered an automated alert, one which has been heard. Erik Cain and his Marines grimly take to the field once again, for what may be their final battle, against the robotic legions of the First Imperium. But facing a ruthless and technologically superior enemy may be easier than learning to fight alongside old enemies. The Line Must Hold (Crimson Worlds V) The robotic legions of the First Imperium burst into human space, destroying everything in their path. Their antimatter-powered fleets drove back the desperately defending human forces, seizing world after world. Directed by the maniacal Regent, the enemy pressed forward with one goal - the destruction of mankind. The Superpowers of Earth, bitter enemies for over a century, have at last banded together to face the threat from outside. Their combined forces have fought stubborn delaying actions to buy time, but they couldn't stop the relentless onslaught. Now the Rim has fallen, and the heart of human space lies before the invaders. On three worlds, mankind will make its stand, and all the power Earth and its colonies can muster has been gathered there. Three worlds - Sandoval, Garrison, and Samvar. The Line. Erik Cain grimly leads his veteran Marines and their new allies to Sandoval, to fight and to hold that world against anything the enemy throws at it. But Cain plans more than just a defense; he intends to annihilate the enemy forces...and he'll sacrifice anything to win the ultimate victory. Even his soul. To Hell's Heart (Crimson Worlds VI) The combined forces of humanity have beaten back the First Imperium invasion. For the first time, the enemy has been defeated in battle. The cost was high in blood and suffering, but the Line held. The heart of human-occupied space has been saved from annihilation. For now. There is little time for the victorious warriors to savor their triumph or mourn their dead. The First Imperium has been driven back, but it has not been defeated. No one expects the fruits of victory to be more than a brief respite. Augustus Garret, Erik Cain, and the rest of the human high command have a decision to make. Do they stand on the defensive, waiting for the massive second invasion they all know will come? Or do they consider another option, one that compels them to face overwhelming odds, and launch a strike that could end the war in one campaign? The attack ship Hornet returned home after a miraculous run through enemy space, and her crew brought with them priceless intelligence…the location of a world of the First Imperium. In the capitals of Earth, the ruling classes call for caution, for the armed forces to stand on the defensive. But on the frontier, Garret and his compatriots are planning something different, and they do not intend to be deterred. They are going to take the war to the enemy. They are going to march into hell’s heart.