General's Bodyguard is a type of melee cavalry in Empire: Total War.
These tough warriors and soldiers have only one task: keeping their commander alive and well in the swirling chaos of battle.
A general can only do his duty properly if these men keep rough and unpleasant fellows from interrupting his calm deliberations about how to kill as many of the enemy as possible for as little loss as possible.
Only the most loyal and fiercest fighters are assigned to a general's bodyguard. Good manners are a bonus, of course, but a strong sword arm and a deadly aim are more use! Their equipment is generally of the finest quality, and their pay is often supplemented from the general's own pocket: they have a sound financial interest in keeping him alive, as well as their honour in carrying out a duty successfully!
As their name implies, General's Bodyguard are the personal bodyguard of a General.
As a combat unit, General's Bodyguard are heavy cavalry with decent statistics, but hampered by their low amount of men per regiment. In practice, most types of cavalry can defeat a General's Bodyguard in a head-on fight. In any case, they are ill-suited to combat as putting them in danger means putting the general in danger.
Despite their overall poorer performance in battle, General's Bodyguards still benefit from fighting for a couple of reasons. First, generals that fight (and do not end up routing) gain bonuses to command after the conclusion of battles - making them a good choice for chasing down routed infantry. Secondly, generals inspire nearby troops, raising morale.