The scouting ability of calvery should increase the mobility of your entire army, especially as a fore running unit giving the bulk of your army the ability to move into enemy controlled territories without fighting.

On your turn, you can move calvery into enemy controlled territory before you move any other unit. Your calvery must fight all enemy units in the territory per normal combat rules. If at least one of your calvery survives, the territory becomes a contested territory into which you can move more units on the same turn.

In a similar way, calvery can move out of a contested territory into an enemy controlled territory in an attempt to make both contested. This simulates the hole punching tactic of calvery. That may prove too strong an ability. With enough calvery, you can slowly march an army right through the enemies defensive lines. But my guess is that it wouldn’t be so easy. If I’m spending all my money on hole-punching calvery, you’ll spend all your money on infantry and artillery and wait for me to come to you.