Ultramarine Corps

The Ultramarine Corps or simply Ultramarines are a branch of the Federal Navy specialised in planetary operations. It is largely made up of infantry and lightly armoured ground vehicles.
The branch was founded during the First Contact War in 2342, when soldiers which had participated in the invasion of the Ur-Han world of Merstrur were brought back to Mars to form a unit specialised in planetary landings. This force would eventually become the Ultramarine Corps, whose creation was formalised in 2346. It is an autonomous corps of the Navy. despite this nominal subordination to the Navy, it is for all intents and purposes independent. Its headquarters are located on Olympus Mons City on Mars. It is led by an Admiral, colloquially known as the High Admiral. 
The Ultramarines are often considered one of the best armed forces in the galaxy, receiving exceptional training and top of the line equipment. They are trained to be capable of dealing with a wide variety of threats, and personal initiative and problem solving is highly regarded within the Corps. Deployment of Ultramarines equates to an operation which requires a swift and efficient execution. The Ultramarines also serve as commandos and often partake in operations of Terran intelligence agencies. 
The Corps is separated into divisions, each one containing about 6000 Ultramarines. There are currently 38 divisions, or about 225 thousand combat personnel.