When in a contest against two Barbarians, both which have at least 1 damage, how is the contest decided?
Does the Barbarian ability stack or only apply once?
I think this is best answered by the example of a 3 player game with one player using Cretin.
Cretin attacks two figures, each belonging to different players. From the official FAQ, Cretin chooses one players figure to run the contest for both defending figures. The result of that contest applies to both figures.
So, in this example, Cretin chooses one figure to run the contest against and apply the result to both figures Cretin is fighting. Barb ability wouldn't stack, since you treat the contest just like it was a 1v1