They can into other people land at least. I can see that Korea is building a military, in fact their building it as fast as possible, filling out lands and stacking units in city as they desperately hope that Bach Gia remains the resting ground of the Digger Hoard. But, looking at it, not many of these are Diggers, in fact, they're all respectable units. If they make their way towards Vigan, they could actually punch into the empire. Stop watching anime and go fight. Weebs, the lot of 'em.