'Combat by Champion' in your nation

[Polska rzczpolspolita]

Yes, it would be considered an honorable way to end a battle that would take much more than one man's life.

[The Anglo-Saxon Empire]

Never really was common, the proto-Luthorians waged inter-clan wars by massed battles with one on one combat, in order to return a slain enemy to their family after a battle they would generally demand payment such as livestock, alcohol, a slave, or a wife. When waging wars against other tribes, or non-proto-luthorians sometimes individual warriors would wander the battlefield before a battle, challenging any enemy soldiers to fight them in individual combat.