There are two types of commanders in the game the alter ego (the one that you named and is station at your homeworld) and NPC commanders (these are responsible for your fleets and colonies). All commanders apart from the alter ego cost you money. Under the commander tab in the fleet button you can see the individual costs for each commander. If you click a commander in the menu you can see his/her stats in the various fields (Trading, Navigation, Research etc). You can also sell or dismiss your commander from this screen.
To alter ego, Commander
As stated before the alter ego commander is the only one who doesnt cost any money. From the tutorial it is known that you can choose which fields you can improve your alter ego commander in and so you should keep in mind what you will be using that commander for later. If you plan to keep him/her on one of your colonies then increase construction and economy. If you plan to use him/her for trading themthen you should increase the trade and navigation. If you plan to use him/her for battles then you should increase the fighting and navigation.
Note for the cost of you can reset your commander stats and redistribute the points.
The NPC commander
The NPC commanders cost 240 credits per level/day. So the more experience your NPC commander gains the more they will cost per day. However once your NPC commander reaches General rank the costs will no longer rise even though they may continue to gain experience. The difference with NPC commanders is that you cannot choose which fields to improve. An NPC commander on a colony will gain points in economy and a little in construction. If they are an explorer, travelling to unexplored star systems, they will gain research and navigation points. If they are the commander of a battle fleet they will gain points in battle and navigation. The NPC commanders stats will improve once a day at the point when they have gained enough experience in a certain field. NPC commanders can be auctioned if you dont need them and want a little cash and well-developed commanders can make you a lot of money.
It should also be noted that the two type of commanders (NPC and the alter ego) cannot be lost during a battle. They commander your fleets from the control centre and so no matter what type of fleet they control be it Trader, Battle, Probe or Mining fleet they will NOT be lost in battle.
Overview of the Commander features
This feature lowers the tax to be paid. Only at auction tax is exempt. Each set point to reduce the taxes by 0.5%. (Minimum achievable duty = 1%)
Reduces fuel consumption by 1% of the fleet (minimum fuel consumption = 5%)
Increases the research progress of 1% per 2 points (or reduces the required research period by 0.5% per point)
Increases the combat skills of the commander by +0.5% damage per point.
Increases the construction of buildings, factories, ships and components by 1% per point.
Increases the production of raw materials per level by 1%.
Lowers the cost of raw material plants by up to 5%.
Lowers the cost of buildings at each level, at 0.33%.
Reduces the flight time of the fleet by 1 / 3%. (Low flight reachable = 5%) (Low flight reachable = 5%)
Increases the value of a vessel to maneuver unknown per point. The maneuvers value is still influenced by other factors.
Per 5 points for Warp tavelling 1AE closer to the goal
The ranks are changed only once daily at midnight if the required experience is reached.
Level Rank Experience Costs GRT
1 Second Lieutenant 0 240 750
2 First Lieutenant 100 480 1500
3 Captain 250 720 2250
4 Major 500 960 3000
5 Lieutenant Colonel 1000 1200 3750
6 Colonel 2000 1440 4500
7 Brigadier General 4000 1680 5250
8 Major General 8000 1920 6000
9 Lieutenant General 10,000 2160 6750
10 General 15,000 2400 7500
How you can gain points
Buildings - Construction of Buildings
Resource Facilities -Construction of resource mines
Research - Finished research projects
Trade - Trading, Auctioning
Ground Troops - For troops trained
Ships - For every newly built ship and component
Battle - All points won or lost during space and ground battle
The Amount of Points Given
Buildings Points = 500 x level of building
Resource Facilities Points = 75 points for each resource mine
Research Points = Research minutes/40 and 20 points for every system you explore
Trade Points - 1000 credits sale = 1 point on auctions and 1 point per NPC trade
Ground Troop Points - 1 point for every 30 ground troops trained, 1 point for every 30 ground troops killed and -1 point for every 30 ground troops lost
Ship Battle Points - 1 point for every 100 resources destroyed and -1 point for every 100 resources lost (resources that were used to build the ship.)