Research Banner Carrier is a unit-upgrade that is typically common to all nine factions in all three BFME games. Banner Carriers increase a unit's level immediately to Level 2 - which brings a small increase to the unit's damage and health-points.
The cost of this upgrade varies depending on the game and faction.
The Banner Carrier himself stands before the front line of the battalion, and any battalions at Level 2 or above who have lost members will gradually grow in number back to their original warrior-amount. (This does not mean that units heal - only Elven warriors heal over time.)
Icon gallery
For Rohan in BFME 1
For Dwarves in BFME 2
For Men of the West in BFME 2
For Elves
For Isengard
For Mordor
For Angmar in The Rise of the Witch-king
For the Goblins in BFME 2