Invading other alliances
Alliance Buildings belonging to other alliances can be invaded, captured, and destroyed.
In order to invade an enemy Alliance Building, select it on the map and start a rally. If the rally is successful, the building will be captured.
Note: Elite Resource Grounds can be only attacked while under construction. The Citadel, however, can be attacked at any time.
Destroying enemy Alliance Buildings
After successfully capturing an enemy Alliance Building, the invading army will remain in the building and start destroying it (more marches can be sent in order to speed the process up). The destruction speed depends on the Guardian used, as well as the amount and the tier of troops taking part in the destruction task.
If the alliance owning the building does not recapture it, the building will be destroyed when the timer runs out. If the destroyed building is the Citadel, the entire Alliance Territory is immediately removed, and all troops gathering resources in the currently utilized Elite Resource Ground will die instantly.
Recapturing invaded Alliance Buildings
The alliance owning the captured Alliance Building can attempt to recapture it by sending a recapture rally. The rally will then fight against the army which is destroying the Alliance Building. If the attempt is unsuccessful, the destruction of the building continues. If the recapture rally succeeds, the remaining units will stay in the Alliance Building and immediately proceed to repair it.
Note: a previously uninvolved alliance can swoop in and take over an invaded Alliance Building! Depending on their intentions, they can either continue the work of destruction or leave and allow the original owners to peacefully send repair marches.
Protecting against invasion
Only Citadels can be attacked at all times. Elite Resource Grounds are immune to attacks except for during their construction phase when they can be invaded, captured, and destroyed. If you coordinate well and complete the construction phase quickly, you will not have to worry about an invasion.
All members of your alliance can garrison your Citadel by sending marches that will remain stationed in it. In case the Citadel is invaded, they will form the defending army and fight against the invaders.
Warning: Alliance Warfare battles do not have a fortification phase. All units will proceed directly to the main battle phase. Battle modifiers of all the garrisoning troops depend on the building's leader, except for the hospitalization values which are calculated per player.