The insignia of a high admiral consisted of unified epaulettes and chest plates, with three bars on the end of each shoulder, plus a flourished diagonal bar on either side of the neck. Imperial High Admirals could command a large fleet of around 20,000 to 30,000 vessels that was identified by its admiral's last name. They could also serve as departments heads in the Imperial high staff and ground forces. High Admirals would also serve as a campaign and theater overall commander.
This was the highest rank that a pure ground force commander could reach, and such a commander would have had command of all ground forces in the Empire.