First one: After being protected an urban domain has gained city status. It only has one hex.
“Domains of land are classified as either civilized, borderlands,or wilderness areas. A newly secured domain will be civilized if it is with 50 miles (8 6-mile hexes) of a city or large town.”
Even if it needs a large town instead of a city how does it work if its only one hex? How can a large town create 8 6 miles of hexes to become civilized if the domain is only 1 hex?
Second one: Does artillery count different from normal missiles weapons? PC researched spell to protect from all normal missiles but wanted to protect from artillery. I would think it counts as something different because a 3rd level spell to protect from all artillery in 30 feet would be a little too much.
Also what is an artillerist and what does he do? He is paid less than anyone else on a team but can oversee multiple artillery machines? And is needed to prevent the penalty?
Question the first: I do not have an official answer, but I assume it’s about traffic. Guarded caravans and the like traveling through an area on a regular basis (as they do for any large town or city) would significantly reduce the number of monsters in the area.
Note that, by my reading of the rules, the hexes are not automatically civilized, but they are civilized if they are part of a domain that is close enough. If it’s just a city in the middle of nowhere, they remain the middle of nowhere. (I am not an Autarch and I might be wrong.)
Also remember that large town and city are pretty big; this is a minimum of 625 families and a class IV market. (That might not sound that big, but there are six entries on the table under large town.)
Question the second: Artillery is not negated by the protection from normal missiles spell. ACKS Core page 84: “The subject of this spell is protected from small-sized, non-magical missile attacks.” Hurled boulders are specifically called out as not being protected; catapults and ballista bolts are clearly not protected either.
Artillerist: According to D@W Campaigns, each artillerist can oversee a battery of 3-5 pieces of artillery (D@W:C pg 23). The full artillery rules start on D@W:C page 43; in summary, artillery without an artillerist fires at half rate and suffers a -4 penalty to attack throws.
I believe D@W:B assumes that all artillery units contain an artillerist, if using Battles instead of Campaigns.
The other thing I would assume about the borderlands / civilised area around a large town or city is that it would function as a sort of sphere of influence. Basically, if you tried to set up an independent domain inside borderlands or civilised area of another domain, that domain’s ruler is likely to object.