Siege of Titan — Michael G. Thomas

Siege of Titan is the first book in the epic 'Uprising' series, part of the growing Star Crusades universe that chronicles humanity's first interstellar confederation that is torn apart by religious strife and extremism.

In the first book of the Star Crusades Uprising series, the bloody struggle is told through the eyes of an illegal pit fighter named Spartan, who is forced to choose between incarceration or military service.  Choosing the Confederate Marine Corps over servitude he begins his thirty long weeks of training.  Together with his group of marines, they are honed into a force ready to be thrown into the meat grinder on the newest and greatest planet in the Confederacy, Proxima Prime. His term of service will soon become one of violence and carnage, as the entire sector is ripped apart by a brutal and virulent religious movement and its shocking plans.

What starts as a series of suicide bombings and hijackings through the Confederacy quickly turns into a full-scale revolution on Prime that threatens the entire planet and quickly spreads to its orbital Naval Station and beyond. As every warship and military transport in the area is rushed to its defence, the fate of the planet and the entire sector lie in the hands of a small number of rookie marines.

The 12-book Star Crusades series includes:
 
STAR CRUSADES UPRISING
Siege of Titan (Star Crusades Uprising, Book 1)
Tears of Kerberos (Star Crusades Uprising, Book 2)
Fires of Prometheus (Star Crusades Uprising, Book 3)
Battle for Proxima (Star Crusades Uprising, Book 4)
Fall of Terra Nova (Star Crusades Uprising, Book 5)
Slaves of Hyperion (Star Crusades Uprising, Book 6)

STAR CRUSADES NEXUS
Legions of Orion (Star Crusades Nexus, Book 1)
Machine Gods (Star Crusades Nexus, Book 2)
Heroes of Helios (Star Crusades Nexus, Book 3)
The Great Betrayal (Star Crusades Nexus, Book 4)
Prophecy of Fire (Star Crusades Nexus, Book 5)
Call to Arms (Star Crusades Nexus, Book 6)
 
These titles are also available as combined trilogies including:
STAR CRUSADES UPRISING: THE FIRST TRILOGY
STAR CRUSADES UPRISING: THE SECOND TRILOGY
STAR CRUSADES NEXUS: THE FIRST TRILOGY
STAR CRUSADES NEXUS: THE SECOND TRILOGY

For more information visit the official Star Crusades website. Keyword Starcrusader.