Commodore

Also called Lieutenant, the rank of Commodore is unique to the grand navy of the Alliance of Independent Systems.
The rank of Commodore was created upon the formation of the grand navy of the AIS, mainly, in an attempt to distinguish the dark and dull naming of the empire's forces, as with most ranks of the AIS navy, as well as to distinguish Commodores from Admirals, an unfilled power gap left in place in the empire forces due to the extreme paperwork and several unorganized attempts at reforming their armed forces.

Duties

The rank of Commodore was placed between the ranks of Admiral -in charge of the joint operation of a vessel with its crew, missions, objectives, and strategy- and the various chieffs of staff onboard one vessel, whose ranks ranged from Hangar Master, to Chieff of Armory, to Captain of possible onboard deployable groups of footmen.
Commodores often serve as relay staff inside a ship, working between the lower officer ranks and the admiral to filter information coming from the lower ranks into the staff, and come in 2 varieties, undistinguished in paper, but fundamentally different in practice.
In one hand there are the "Staff Commodores", which include personnel which tends not to be in the command center/pilothouse of the ship, but rather move around the ship to make sure their designated stations are on par. They are often accompained by a very small squad for protection, and tend to not have seats in the command center.
On the other hand there's the "Cabin/Seat Commodores", which include personnel in charge of, mostly, onboard systems like communications, navigation and weapon systems. They are often seated around the Admiral of the ship and relay orders and news up and down the chain of command as necessary.
The third, rarer, variation of Commodores are the so-called "Field Commodores". These are officer personnel in change of small outposts, stations, standing vehicles like command centers or small prisons, and more specifically, planetary garrisons of all types. Field Commodores are the ones responsible for mantaining garrisons on par with regulations, and serve as the highest ranked personnel of most soldier garrisons, reason why they tend to be respected as generals without having such rank.
A Famous Field Commodore would be Daego von Kolom during his stance in the Yaith Blockade, during which he served as chieff officer of the Garrison of Yokka for a brief period of time.