13th Infantry Regiment

The 13th Marine Infantry Regiment, also known as the 'Hell Regiment' is one of the UNSC's most elite and veteran regiments, outside of special forces. 
==Origins==
The unit was original risen from a large amount of Europeans or colonists of European descent to replace a deactivated unit from the Human-Covenant War and shortly after mobilisation was sent to defend the colony of Cerbere. Here, they were baptised in a test of fire and blood. 
==Remnant War==
While Cerbere was defended by a Naval battlegroup and a collection of ground based AAA positions and anti capital ship missiles, an infiltration force of Brute Stalkers destroyed these positions before the Battlegroup was attacked by a Remnant invasion force. Unable to stop the torrent of PHantoms screaming towards the surface and with no ground positions to halt them, it was up to the 13th Infantry Regiment to defend the colony. As the only defensive force groundside, par militia forces, they decided to centre their defensive power and evacuated as many civilians as they could to the UNSC command post and surrounding town. They centered their last few AAA systems here as well, giving them some moderate defensive power. The portside town was a veritable fortress of machine gun nests, snipers, improvised fortifications and determind infantry, leading up from the port killing zone onto the steep hill through the town then to the UNSC command post at the top, with its back to sheer cliffs. The Brutes soon landed on the beaches and in the open port area with their dropships and were immediately fired on. As they tried to gain a foothold the 13th pushed them back with every opportunity, almost pushing them off the dock a few times. However, throguh sheer weight of numbers the Brutes secured the dock and pushed the 13th back up the hill, with the 13th refusing to give ground. Even as the Brutes made it to the offices further up the hill, the lower town centre and the church (where a collection of civilians and Marines refused surrender, fighting to the death even as the Brutes broke in and massacred them) and even pushed them out of the upper town centre, despite considerable defences. The battle has many tales of heroism, one of the most famous being when Captain Giovanni, CO of first company, strapped excess amounts of plastic explosives to his personal Warthog in the form of a shaped charge and used it as an improvised HEAT weapon, driving it into a marauding Wraith, long after his men had ran out of missiles, rockets and other tank weapons. By driving his 'Hog into the Wraith and destroying it, along with a pack of surrounding Brutes and holding up the attack force, he saved the life of many of his men and gave them enough time to evacuate to the fortified outpost at the top of the hill. Here they fought to the death, engaging the enemy in a brutal melee in the labyrinth of small buildings at the foot of the command tower, their sheer tenacity throwing the Brutes back. They held this position, even under artillery fire and Brutes executing POWs in front of them up until they were relieved by the UNSC Assault Carrier, Hera, having arrived with the tenth fleet to end the siege and repel the invaders. Expecting a massacre, they found the 13th, although reduced to 1/3 of their original size, still alive and jovial. To this day, no surviving member of Cerbere has ever admitted to having needed to be rescued. 
==Necros War==
In the Necros war the 13th was present at Gundark and was caught out by the Necros blitzkrieg advancement and stuck in the Gundark pocket. However, with their backs against the wall, the 'Hell Regiment' as they had become known, mostly for surviving through hell, showed exactly how dangerous they were, single handed, along with aid from an air contigent and a Marine airgroup, held the only route across the wide Koan Canal, holding against a division sized force, stopping them from getting their armoured units and super walkers across into the vulnerable areas it protected.
==Subordinate units==
*1st Infantry Battalion
*2nd Infantry Battalion
*3rd Anti Tank Battalion
*4th Reconnaissance Battalion