The military of Tannish is expansive and a little more complex than it really should be. There are a handful of divisions within the Legion, including the Legionnaires (the ground troops), the Sea and Sky Corps, the Engineering Department, the Battle Wizards, and the Inquisition.
The Legionaires: they cover the whole ground forces, including land vehicles. Almost everyone in the Legion ends up here. Occasionally, rising to the other divisions happens (and it's not uncommon), especially if you show promise. There's not a lot of choice when enlisting... And draftee's have no choice at all.
* Steam Knights are exclusive to the Legionaries. It's often considered unwise to pilot one on an airship or boat.
the Sea and Sky Corps: the carriers and battleships that dot the waters and air belong to this division. The air forces are fairly new, only becoming prominent in the current war against the Elves.
*Dragoons are units that possess special dual propler jump packs that allow them to hop from one ship to the next. These are some of the bravest and skilled soldiers in the Legion, as it takes balls of steel to jump from a ship thousands of feet in the air onto another one that may be a few hundred feet away.
Engineering is in charge of repairing and developing new technology. These folks are pulled from factory jobs to go up behind the frontlines to insure that tanks, steam knights, and ships are operating. They receive some combat training to defend themselves in the worst case.
*Artificers are the rare engineer who delves into something stranger than normal. Telsa weapons are their domain.
The Battle Wizards are the unlucky few went to the Mage's Association who claim Tannish home. As part of a pact when a Tannishian joins the Association, they must serve the Empire when called upon. While few in numbers (often times a unit only consists of 2-5 mages), their power is enough to support most war efforts.
*Alchemists, while not full mages, have proven themselves quite adept at battle. Their bombs and alchemical shells more than compensate for their lack of spells, and doesn't interfere with guns.
The dreaded Inquisition keeps the entire Legion in line and serves as the Emperor's hidden agents. They rarely operate in the open, and worst yet, they are armed with Artifacts, making them incredibly dangerous. Deserters and traitors are often put down within days by these Inquisitors. The very fear of Inquisitors is just enough to keep most of the Legion serving the Emperor.