In the previous Rome: Total War expansion and base game, particularly in historical battles, no real life leader got their own unit like Alexander did.

Alexander is the only historical leader to get a unique unit.

The only difference is that his unit is far larger (in skirmish battles at least, it's only a few men more in the campaign).

Alexander has identical stats to regular Companion Cavalry.

Equipped with protective cuirasses and wielding the xyston, a double-ended stabbing spear their mobility makes them the hammer of the Macedonian army! The development of the devastatingly penetrative wedge formation completed the transformation. The military reforms of Alexander's father Philip altered the function of the cavalry from merely screening the army's flanks to a more proactive role.

The Companion, or hetaroi, cavalry are recruited from the nobility and are a military elite. Unlike his Persian adversaries, Alexander is a leader in the heroic mould, always in the thick of the action, an inspiration to his men and a terror to his foes! The Royal Squadron, or basilike ile, is a double-strength unit of Personal Companions under the command of Alexander himself. Alexander is a type of heavy cavalry unit available to the Macedonians in Rome: Total War: Alexander.

Rome total war alexander