The Eagle and the Radiant Cross has many unique factions. Each of these has its own seperate playing style. Not all of these factions are currently in game. However, they are mentioned in the game's lore.
- The Holy Swadian Empire - Equivalent to the Holy Roman Empire. The core of their armies are dense blocks of pikemen supported by Doppelsoldners and heavily-armored knights.
- The Vaegir Tsardom - Based on Russia at the time of Ivan IV Vasilyevich. The Vaegir army favors masses of armored men wielding large berdiches supported by the semi-professional Strelsy.
- The Ormeli Empire - A force based on the Medieval Ottoman Empire. A mix of horse archers and heavy cavalry supported by the Janissaries.
- The Laurian Kingdom - Based on the native Spanish Kingdom during the late Renaissance. The armies of Lauria use the same style of warfare as the Swadians, forming their lines around blocks of pikemen.
- The Lion Throne - With huge blocks of heavy infantry supported by lighter auxiliaries, the Lion Throne resembles the Roman Empire on steroids. Occupies former Ellisian territory after the downfall of the Ellisian Empire and the burning of its Emperor at the stake being its excuse for invasion.
- The Imperial State - Based on Prussia during the unification of Germany. The Imperial way of war is unique, in that it revolves around lines of gunpowder infantry and has no dedicated melee infantry troops whatsoever.
- The Haelmar Union - Based on 17th Century Sweden/Scandinavia with hints at the Kalmar Union. It uniquely consists of three "sub-factions", which represent the major countries of the Union. The Haelmarian Army consists of Colonial Militia as well as mediocre pikemen and long-ranged musketeers. They are supported by medium Hackapells.
- The Grand Duchy - Reminiscent of the 16th-18th century Polish. Primarily a cavalry nation, it has the famed Winged Hussars, heavy lancers that can cut through a formation easily. It is supported by mediocre infantry and other cavalry units, though it does have a few Nirdamese refugees at its disposal. It is considered to be an "unfinished" faction.
- There are also many different peoples offering their services as Mercenaries .
- Dual Monarchy - Based on a mix of Russia, the Sassanians and Austria-Hungary, it fielded a large variety of troops, making it one of the most flexible armies with excellent Nirdamese Archers. It had decent cavalry and infantry to support it in the field also. It was defeated when King Leiss was killed in a great battle against the laurians along with most of the nidamese branch of the Kingdom Army.
- Ellis Empire - Based on the Byzantine Empire, with references to Classical Greece and Rome. It fielded an army consisting mainly of excellent spearmen, though was supported by the Lion Throne's Brigade of the Radiant Cross in its death throes. It was destroyed after the Emperor, Nikephoros, was defeated and burnt at the stake for Heresy by the Swadians, for he had converted to Filaharnism. Ellis was soon subjugated by the Swadians but reconquered by the Lion Throne.