[Skimmy2]

As it stands, the current military and command structure is listed as:
Armies - General
Legions - Major
Battalions - Colonel
Platoons - Captain
Squads - Lieutenant

In so far as enlisted vs officers go, I was preparing a needlessly long 3-5 paragraphs explaining the intricacies but this isint Milsim 2: Rise of Kinu.
So to tl;dr:
Commissioned Officers make decisions
Non-Commissioned Officers ensure that said decisions are organized and carried out.

The following will be my proposal for more Fantasy ranking as well as for cultural differences per nation to improve roleplay. Though I encourage any changes, counter points or opinions, as im not exactly the authority on this lore.

Sigrogana:
COMMANDERS
--Secretary of Defense, Secretary of War
--General
--Sergeant Major General/Major General
OFFICERS
--Colonel
--Captain
--Lieutenant
PERSONNEL
--Ensign
--Sergeant
--Soldier

Responsibilities:
Generals command Armies
Major Generals command Legions
Colonels command Battalions
Captains command Platoons
Lieutenants Command Squads
Ensigns are Senior personnel whom assist a Squad's Lieutenant, they do not command a "Corps" on their own.
Sergeants are veteran soldiers whom carry out the orders from the Lieutenant and provide guidance and experience to Soldiers. They are expected to be competent in their duties and ensure that they are setting a good example to follow.
Soldiers are the bulk of Sigrogana's army, whether volunteered or conscripted in an emergency. They are adequately trained and equipped to ensure the sovereignty and will of the Empire.

Notes:
The Sigroganian Empire is the largest Nation and with a history of long military successes paired with competent leadership of their Emperor.

Because of this Sigrogana's Armies are Large and unwieldy, relying upon lower "corps" initiative to ensure flexibility and speed to threats.

A Sigrogana Squad is considerably larger then most other nations, close to even twice in size if it's at full strength. Due to these large formations, a Ensign assists the Lieutenant in commanding and controlling their Squad, with Sergeants providing much needed experience to the large number of Soldiers that have seen less combat. Some of these Sergeants would be veterans of the Oniga Sigrogana War, though that War being over 50 years ago has seen veterans of the conflict gradually be aged out of service.

Rank wise, Sergeant Major General is the historical rank, and why "Major General" is a lower rank then "Lieutenant General" IRL. The Sergeant may be dropped if it proves too confusing.
If we wish to keep it simply as "Major" for short and sweet, then alternatively we can switch Major and Colonel's places within the Structure.


Oniga:
Language: Onigan/Common
COMMANDERS
--Shogun/Marshal
--Daimyo/General
--Bugyo/Major
OFFICERS
--Kumigashira/Colonel
--Kogashira/Captain
PERSONNEL
--Ashigarugashira/Lieutenant
--Ashigaru/Soldier

Responsibilities:
The Shogun is a position appointed directly by the Tennou to lead his Armies.
Daimyo are in charge of leading a House's Army, the Position of Daimyo is either filled by the House's Head themselves or a trusted commander to do so.
Bugyo are appointed by the Daimyo to handle more logistical and tactical affairs of the army, they are in command of their own Legion.
Kumigashira command a "Kumi", or "Set" in the Common language, "Sets" are the traditional tactical units of an Legion to maneuver, they are roughly equivalent to a Sigroganian Battalion.
Kogashira are in charge of a Platoon and assist the Kumigashira in leading the men.
Ashigarugashira command a squad of Ashigaru and are the lowest leadership role of the Army.
Ashigaru, or "Foot Soldier" are the common soldier that makes up the bulk of the Army.

Notes:
While all are subservient and loyal towards the Tennou and royal family, the noble houses and clans of Oniga have large sway over politics and affairs.
The strongest noble houses provide their own armies to serve the Tennou, and they are not without some autonomy to carry out their duties. Daimyo are either the Heads of a Noble House or, more often then not, a trusted retainer to serve as a General and lead the House's Army.

If a 3rd Personnel rank is desired, then "Samurai" can take on the role of Lieutenant and Ashigarugashira can be lowered to a "Sergeant".
While I couldnt find any actual lore on Samurai in Sigrogana, its pretty safe to assume that they exist unless Dev says otherwise, and they would be the equivalent of a Knight in title more so then military rank.


Chaturanga:
COMMANDERS
--Marshal
--General
--Baronet/Major
OFFICERS
--Knight Commander/Colonel
--Knight/Captain
PERSONNEL
--Squire/Lieutenant
--Pawn/Soldier

Responsibilities:
The Marshal is appointed and voted on by the Council of Chaturanga to lead it's armies.
Generals lead an Army and are composed of the most talented tacticians within their city.
Baronets are a noble title, appointed by a Baron and responsible for all of the Knights within their land. They command a Legion.
Knight Commanders are veteran knights recognized by their deeds and given command of a Battalion.
Knights are the fulcrum Chaturanga's military doctrine, forming the backbone of it's Armies. They Command a Platoon of men.
Squires are Knights in training, serving the Knight that they are subordinate to and leading a Squad of soldiers to prove their worth and hone their training.
Pawns are the humble foot soldier, volunteer mercenaries whom arent proper knights as of yet, they support and fight alongside knights in battle.

Notes:
Chaturanga's military is highly competent and elite, acquiring a reputation for their formidable Black Knights that are nigh unmatched in the world.

Their government is a council based system with noble houses and titles.
Unfortunately the noble houses and inner politics of Chaturanga are less fleshed out as of now, as I have not much known on their peerage titles and land structure. Because of this, the ranks are most likely to change.
IRL, "Baronets" are a title roughly inbetween of a Knight and Baron and were historically responsible for all of the Knights within a Barony. It helps to think of them as a "Baronet" is to the "Baron" as a "Viscount" is to a "Count".

If a 3rd Personnel rank is needed, "Man at Arms" can fill the role inbetween of Squire and Pawn as a "Sergeant" in rank.


I was gonna finish Alstalsia but I literally spent all day researching and writing this, so I'll just stop for now and see what everyone thinks.