The following factions are present in the Viking-Invasion exclusive campaign set in the British Isles and Scandinavia. In addition to these factions, the Aragonese, the Normans, and the Hungarians become playable in the original campaigns when Viking Invasion is installed.
The Vikings start in Jutland and Norway and have special units, especially naval units, which can travel far and fast. Unlike all of the other factions (which are uniformly Christian), they are pagans and receive extra cash rewards for destroying buildings in a province. They can be converted to Christianity by the other factions, which can reduce their potency. The game has been designed, in order to boost historical accuracy, that Vikings have exceptionally powerful ships and raiding bonuses and the fact that they will quickly go bankrupt if no raids are made. Their faction colour is white.
Mercia is an Angle faction, and starts in the English midlands. This faction's colour is light blue.
Northumbria is an Angle faction based in northern England. These are usually the first target of the Viking raids, especially in Beornice. This faction's colour is yellow.
Representing Wessex based in western England. This faction's colour is red.
The Picts are a Celtic faction inhabiting the most of Scotland and control quite a few provinces, though they are generally unprofitable. Their colour is brown.