. As an officer, you could change your title as you advance, going from Lieutenant to General (or from Ensign to Fleet Admiral, for those in the Navy) as you advance in level.
While the misconception that the Warlord class implies legitimate position or power or must automatically be the party leader (in the sense of bossing players around) is one of the complaints we here about the class, and any military rank or legitimate-authority name is thus pretty fraught, I'm increasingly convinced there should be a
sub-class that represents just that, because particularly talented/skilled officers might be modeled as Warlords. While Captain or Commander could be used for such a sub-class, I suppose Officer makes some sense, since you can, as you say, work promotions into it, and it's just generally less specific.
Though, D&D class names aren't assumed to be used by the characters, themselves (not since,
maybe 1e level titles). A "Captain of the Guard" could be a Warlord, Fighter, or Ranger - or an NPC-stat-block Guard - or even a Rogue or caster of some sort, in a high-magic setting like FR. Even if a subclass were called 'Captain' the character might be called "Lieutenant" or "General" or "Hipparch" or whatever in accord with the rank he earns in his adventures.
And it's neither here nor there, but I built a pretty great "battlefield leader" out of a human bard with the Soldier background and the Inspiring Leader feat. What's in a name, really?
In the name "Bard" in D&D?
9 levels of spellcasting.
