Paper - rock - scissors type game

[Holywhippet]

On one of the islands (I forget the name, it's on one side of that really long bridge) you can find the town mayor in one of the huts. He challenges you to a game - I think it's called Knights and Priests or something like that. Does that game actually lead anywhere? It seemed like we just kept calling out the name of units until he called out "the strongest unit in the game" and won.