In the modern military, the First Sergeant (the Shirt) is a very important person to nearly all enlisted folk. A good Shirt can and will bend over backwards to ensure that each and every one of their troops are being taken care of properly. A bad Shirt can totally destroy moral with neglect of the troops, trying to run the unit from behind the commander, or just plain being incompetent. Ive had both types during my time in, and at one point the Shirt was both cases at the same time. So, what is a First Sergeant supposed to be doing? They are the voice of the enlisted to the commander.
But what about in 40k, where Imperial Guardsmen are tossed into the maw of war in their millions? I think there is still a role for the Shirt, though not exactly the same as modern times.
The First Sergeant is the most senior sergeant in an IG company, and its his job to ensure that every soldier understands their role in a mission. The Captain will usually give the company a rough overview of the plan, but it falls to the First Sergeant to explain the specifics to the assembled squad leaders and specialists.
Up to one Infantry or Command Squad veteran sergeant in an IG army may be upgraded to the First Sergeant for +20pts. The army MUST be lead by a Senior Officer (the junior officers are not experianced enough to work well with a First Sergeant, and Heroic Senior Officers are too busy to keep an enlisted person informed). The Senior Officer grants an additional +1LD up to a max of LD10 when other units use his LD with a vox-caster, as long as the First Sergeant is alive.
For the Adeptus Astartes, the First Sergeant is usually the "heir apparent" in a company, the Space Marine that everyone expects to take over when the current captain falls in battle. Typically this is the Sergeant of the first Tactical squad, but it is not unknown for it to be a different squad, or even from the Assault or Devastator squads.
Up to one Command Squad, Tactical Squad, Assault Squad, or Devastator Squad Sergeant in a Space Marine force may be upgraded to the First Sergeant for +10pts. The army must have a Captain in it, though this may be one of the special character Captains. The First Sergeant may use the Captains LD from anywhere on the table, as long as he is alive.
What do you all think?
*EDIT* Tightened up the restrictions of choice for the Space Marines, and lowered the cost.