The first captain commands the royal guard, their first duty is to the ruler of the land to whom they swear an oath, it is the greatest honour in the monarch's army. While a non-battlefield role they are the most skilled of combatants who train everyday with every weapon imaginable.
A first captain will have the role for life, or the monarch dies, as the new monarch will appoint a new first captain as a matter of tradition, although it can often be the previous one. In rare cases a first captain can greatly displease the monarch and be retired, usually this comes with exile.