The Circle of the City is made up of druids living in cities to guard and to maintain the balance between nature and civilization. Druids of this circle do not reject technology and metal, but rather are very pragmatic about the tech they use. This circle thinks that metals come from the earth, and because of that, they have a natural place in the world.

Starting at 2nd level, you gain proficiency with dart guns and pistols (including machine pistols).

Also at 2nd level, whenever you use your Wild Shape feature, your shape is made with metal and pieces of the city, more similar to a construct than a beast. While transformed into a beast, your AC increases by your proficiency bonus and the Constitution score of the shape increases by 2.

Starting at 6th level, the Constitution score of the shape increases by 4.

At 6th level, while transformed into a beast, you are considered a construct, you gain a +1 bonus to attack rolls and your attacks count as magical for purpose of overcoming resistance and immunity to nonmagical attacks and damage. At 8th level, the attack bonus increases to +2

At 10th level, you can wild shape into a city guardian for 1 minute. After using this feature, you must finish a long rest to use it again.

At 14th level, you cannot be charmed, paralyzed, petrified or poisoned and you are immune to poison and psychic damage. Additionally, you can wild shape into a city guardian twice before a long rest.