For the unit, see Line Infantry.
Line Infantry are a type of infantry in Empire: Total War. They form the backbone of most armies. In terms of defensive capabilities and staying power, they are nearly without peer.
Line infantry form the heart of any army in Empire: Total War. Durable thanks to their high numbers, excellent defense, and high morale, line infantry form the lines of battle and fight in the most pivotal areas of the battlefield. In a head-on fight, a line infantry will be able to beat almost any non-line infantry regiment (with the exception of a well-angled and timed salvo of canister shot fired from an artillery piece). Line infantry hold the advantages of superior numbers (and therefore superior firepower when Fire by Rank is researched), morale and defensive capabilities.
Line infantry have several technology upgrades available to them. Plug Bayonets increase their melee capabilities, but require the infantry to equip them manually and force them to remain in melee mode until after the battle; Ring Bayonets are permanently and automatically attached, and still allow the infantry to fire, but reduce their firing rate; Socket Bayonets neither sacrifice shooting abilities nor speed while providing the line infantry with good melee capabilities.
Bayonet technologies aside, line infantry benefit enormously from the Fire by Rank, which enables all ranks of the infantry to fire one by one as opposed to just the first rank. Fire and Advance gives line infantry the ability to close in on enemies while simultaneously delivering fire to against them. Finally, Square Formation allows line infantry to form a square, reducing their firepower and sacrificing their ability to move but giving them a powerful defensive bonus against cavalry.
Every major faction in the game has slightly different line infantry. The British, for example, have some of the finest all-round line infantry in the game, while Russian line infantry have very poor shooting characteristics but have unparalleled charging bonuses. The Ottoman equivalents of line infantry are the Isarelys and the Nizam-I Cedit infantry, while the Maratha Confederacy have Bargir Infantry and Sikh Musketeers.
Austrians have the advantage of having line infantry regiments with 25% more manpower. For example, on ultra settings a full non-Austrian regiment has 160 men; Austrian regiments have 200, instead. On the other hand, Austrian line infantry have generally very poor stats and are the most expensive to field.
Line infantry are at their best when their flanks are defended by yet more line infantry. They also serve as a shield for less durable units, such as Grenadiers and generals.
Prior to the introduction of fire by rank, commanders can increase the effectiveness of their line infantry by forming them in long, thin ranks, increasing the firing frontage of the regiment. However, this formation has some drawbacks. This increases the exposure of troops to the enemy, providing more targets and increasing casualties. Should cavalry attack, they can easily break through thin lines.
With the introduction of the square formation, line infantry gain some protection from the cavalry threat, allowing them to quickly form squares in response to oncoming cavalry.