I'm watching Star Wars Rebels and Admiral Thrawn is invading. Will an Admiral know about this?

The Pacific Theater of World War II consisted of two separate campaigns, which I call the Southern Campaign and the Northern Campaign. Both campaigns had maritime and land components.

General Douglas MacArthur of the United States Army commanded the southern front, primarily overland through New Guinea and into the East Indies and Philippines. However, the Northern Campaign involved contiguous land and abundant water, so full command was given to the United States Navy, under the command of Admiral Chester Nimitz. The point is, actual command of the Army and Marine Corps rests with Army and Navy officers, not the Navy.

The biggest similarity here is a joke: "The army is the bullet fired by the navy": that is, if the army cannot reach the battlefield first, it cannot fight. This is a huge amount of moisture from Hawaii to Japan.

In the world of science fiction, there is a logical reason for ground force commanders to be accountable to space force commanders: Ground strikers first need spacecraft to take them to the target planet. In many cases, they may also need space forces to control space above the planet to prevent it from being cut off or destroyed from orbit. Therefore, senior officers like the Imperial Grand Marshal need to be familiar with at least the basic principles of surface warfare tactics so that they can have their forces in the right positions to provide the appropriate support. Briefings and inter-force communications do just that. (Incoordination between the army and navy was one of the reasons for the failure of the Gallipoli campaign: at one point, an Indian regiment made a breakthrough, only to be accidentally bombed by the Royal Navy because they had no radios and could not cancel the scheduled bombing in time.)

However, direct orders are a bit of a stretch. A more likely scenario is:

However, direct orders are a bit of a stretch. A more likely scenario is:

In The Empire Strikes Back, Darth Vader is the Commander-in-Chief of Death Squadron (under the authority of the Emperor). Admiral Kendal Ozzel and later Admiral Firus Piett were Space Force commanders. However, there was a split in the chain of command: it was not an admiral but an Imperial Army officer, General Maximilian Wells, who commanded the landing ground forces.

In the Age of Sail, it was common for captains, flotilla commanders, and even admirals to paddle ashore to direct marines, and in rare cases even armies, in battle. There is a difference between the Marine Corps and the Army. Marines are a special class of soldiers that specialize in ship-to-ship boarding operations and amphibious assaults.