Expanding Mother Base and collecting weapons and resources for it will help to develop the base even further. In turn, the soldiers you’ve recruited into Diamond Dogs will also level up along with the expansion of Mother Base and they’ll be better able to assist Snake on the field. Just like in Peace Walker and Portable Ops, your various units in Metal Gear Solid V: The Phantom Pain will learn new skills and be able to develop better gear for you as their levels increase.
Similarly to previous games, Metal Gear Solid V will also allow you to personally handpick your soldiers and assign them to various departments. Alternatively, you can allow Ocelot and Kaz to do the assignments for you. The soldiers you recruit into Diamond Dogs will be automatically assigned to whichever department best suits their stats, but you’ll be able to change up the roster as you see fit.
As the units level up, they’ll be able to assist Snake by providing intel, supply drops and even backup on the field.