The Flamethrower attack has a high Rate of Fire (the highest of all units) and deals splash damage with strong multipliers against infantry, buildings, and ships. However, it is countered easily by cavalry and other artillery as an infantry unit. Unlike true artillery units such as the Mortar, the Flamethrower can take some time to destroy buildings, especially with its short siege range.
The Flamethrower is best used as a support unit for infantry against massed enemy infantry.
"The flamethrower was the first use of gunpowder in warfare, before it was imbued with enough saltpeter to explode. The Chinese flamethrower design, the Pen Huo Qi, was based on a seventh-century Byzantine model, which featured an inconsistent spurting action. The Chinese desired a more continuous flame, and achieved it by developing a dual bellows system. Two bellows allowed for the creation of an unbroken stream of the chemical fuel naptha, which could then be ignited.
The Chinese flamethrower was used both as a defensive weapon and a siege unit. It was often fixed on a wall, positioned to fire down on incoming soldiers and siege weapons. However, the most common depiction of the flamethrower portrays it as mounted on a four-wheeled pushcart. This mobility most likely allowed the flamethrower to be used on the battlefield, to deter enemy attacks, as well as to project a shield of flame for advancing soldiers."