Trying to pick the one single key system in Ashes of Creation is like trying to bottle smoke. While the Node system is the predominant system of content creation, the Castle System and Castle Region mechanics are no less important because while they have their own independent systems, they are also directly tied into the Node System.
In order to keep the emphasis on the Node System, I will do tie-ins back to the Node System as often as I can to ensure emphasis remains on the Node system.
Finally, it is important to emphasize that Castles are primarily guild content. While there is a lot of content for members of different guilds working together (Node Siges, Node Wars), the seizing and management of Castle is primarily a Guild and a Guild-Alliance theme.
When the game first launches and the players arrive on Verra, everything in the world is void with the exception of the Divine Gates, the Starter Towns, and the Castles. The castles are going to be inhabited by NPCs. In order for a guild to assume control of the castle they are going to have to defeat the NPCs. Should they manage to accomplish that, the Guild Leader will become the regional monarch.
As stated in the The World of Verra section, the World Map of Verra is divided into 5 Castle Regions. The center of power for this region is the regional castle, which will have a proper name, which no doubt will either be the name for the castle region or will serve as the name for the castle region.
So far we know of a Dünzenkell castle named Milnar, and an Aelan castle named Korgan.
It is important to stress that Castle Regions are fixed, they do not change as a result of player actions. It is also important to note that Zones of Influence can cross over a Castle Region border. This is going to be a very interesting dynamic as the regional monarch is no doubt going to want the Nodes on his side of the border, because more Nodes means more taxes.
Just like there are taxes in the Node System, there are also taxes in the Castle Region. The primary difference between the two taxes types is that while the Mayor of a Node cannot remove any of the taxes for personal use, the Regional Monarch can remove a portion of the taxes to use however they see fit.
We do not know what percentage of the tax system can be removed, but we do know that a monarch that drains too much out of the tax system leaves his region open to attack.
Just like the Monarch can set a tax on his region, the monarch can also influence his region with different influence dials that affect crop yields, resource spawning, event spawning, and can unlock different types of buildings in Nodes.
There are many ways that the Regional Monarch can assist during Node Sieges. A very direct way is marshalling his guild and marching them down to the Node to participate in the siege itself. A more indirect way is by using some of that tax money to support the Node with tangible benefits like paying for gates and walls, by putting siege schematics in the siege prep store, and by hiring NPC (or even PC) mercenaries to fight for the Node.
Other than the political power and direct control a Monarch has over their region, each monarch has access to one of the limited flying mounts in the game. Each monarch will have a Dragon that allows them to travel from their seat of power (The Castle) to wherever they are needed in the region. This true flight time will be limited, as is a reward for being the regional ruler. This mount also has PvP capabilities, so it is going to be something to consider when sieging the Castle or one of that Castle’s Nodes.
Additionally, up to five officers in the guild will have access to Wyrmlings on Siege day depending on how successful the guild is at building their Castle Nodes during the Siege Prep Month. These Wyrmlings are flying mounts usable only on Siege day. More details to come later.
Castle sieges are covered in more detail in the PvP section, but the summary of the situation is Castle Sieges will occur every fourth week, however, this does not mean that the Castle Siege is only a once a month event. Even though the actual assault on the castle only takes place every fourth week, the other three weeks of the month are going to be busy with the owning guild having to build up their three specific castle nodes.
Additionally, the process of sieging a Castle is not going to be easy. To launch a siege against a castle a guild leader must first be in possession of a Siege Declaration Flag. This requires a master in each of the three Artisan Trees (Gathering, Processing, Crafting). We are not sure what happens if two guilds try to drop a Siege Declaration Flag at the same castle at the same time. This is something we are waiting on an answer for.
In order to Siege a guild must be at a certain guild level, as of right now we do not have much information on Guild Levels.
Attached to each castle are three special nodes. To call them nodes is rather unfair, and Intrepid will be changing that giving them proper names, but for the moment players are used to hearing them referred to as Nodes so that is how Ashes 101 will present them.
These three special Nodes are always Military and they are capped at Stage 3. These nodes exist outside of the traditional Node system. They cannot influence their neighboring nodes stopping their growth, and they cannot have their growth stopped by neighboring Nodes.
Each week during the siege cycle, one of the Nodes will need to be developed. This will require members of the owning guild (and possibly their alliance) to do experience earning events inside that Nodes ZOI, so that it can level. It will also require the guild to bring in Caravans for all the things the Node requires to level up. This is going to create an enormous amount of PvP as anyone who is planning on sieging the Castle, is going to be highly interested in disrupting all of the Castle Node Development.
Each week there is also an event at the Castle Nodes. This is going to be an opportunity for potential siegers to disrupt the Node and for the castle owners to defend what they have built. The success of the defense of these Nodes correlates to the accessibility of the Wyrmlings for the defending guild on Siege Day.