As the Hun horde swept across Europe, they forced the Germanic tribes into exodus. These warlike peoples spread within the borders of the Western Empire and, by dint of looting and war, will eventually cause the collapse of the Empire. In the twilight of antiquity and at the dawn of the Middle Ages, the so-called barbarian nations founded kingdoms on the former imperial territory.

In Barbarian Kingdoms, an asymmetrical and competitive strategy game, each player controls their own nascent kingdom and competes for supremacy over Western Europe. The first player to control seven territories or to eliminate two opposing kings wins. On a turn, each player chooses and resolves a single action of their choice:

Recruitment: deploy a warrior from the reserve by paying a cost
Taxation: collect money from the provinces in their kingdom
Assault: invade a province or attack an enemy unit
Maneuvers: reposition their units in their provinces or towards the sea
Claim: try to take control of a province by paying a cost
Assault and claim actions can be immediately challenged by an opponent and resolved by a battle. During the battle, a bribe may be paid to the opponent to try to reverse the outcome.

Players must be vigilant in positioning their forces (with the constraint of a maximum of one unit per province), keep an eye on their opponents, and take advantage of their two asymmetrical powers: that of their kingdom and that of their king.