SE seems to have toughened up campaign again with the last update. Instead of bemoaning however I've been trying to figure some general things out. Campaign has been around for a long time now but there doesn't seem to be much more than a vague, unacknowledged understanding of how it works. Even the wikis pretty much parrot the old info SE produced. This is info I've taken from reading the campaign threads and my own experiences. Please tell me what seems right or wrong and share any info you may have.
Campaign Battles:
Campaign battles are carried out according to their army's weekly policies and strategies. A single campaign unit has a time limit of one earth hour, however having campaign tags and fighting multiple overlapping units can last hours longer. Not many people seem to know that the intel npc actually lets you know which battles are being prepared if recon level is high (select the "latest intel" option). Battles are waged by players and the participating armies and their specific units. Every army is comprised of 15 different units. There are 5 offensive units that can be freely sent to any zone in its region. Every zone also has 1 specialized unit divided between the 5 regional zones which only focus upon attacking or defending their unique area. Lastly there are 5 units for reconnaissance, ally support, or technological weaponry.
Unofficially there are 5 types of battles. They are:
1: Offensive: Players attack a beastmen fort.
2: Defensive: Players defend an allied fort.
Reconnaissance battles: Usually reconnaissance units are sent out during a longer already occuring battle, however they can take place as their own individual battles (and it's quite annoying). Note that recon units always approach from their corresponding areas. They cannot spawn at a fort even if their army owns the zone.
3: Reconnaissance sabatoge: A recon unit is sent to damage an enemy fort. 6 mobs make their way to the areas fort. Once they reach it they quickly plant a bomb (at this point they are immune to attack) and warp. All 6 recon enemies must be defeated in order for their unit to "retreat" instead of being "victorious".
4: Reconnaissance fort repair: A recon unit is sent to a greatly damaged fort to make instant repairs. If a fort becomes seriously damaged (usually about 50~60 levels of damage) a recon unit can be sent out which instantly recovers a large amount of fortification with every successful recon NPC that is able to reach it. Recon beastmen do not aggro they will move along unless acted upon. Once they have been claimed they will engage like a normal enemy, although if too much hate is lost they can still return to moving toward the fort. Effective ways to slow them down are sleep/gravity/bind which should stick easily. The "goal" area for the recons to reach is a somewhat large radius around the fort, so if you are trying to prevent them from reaching it, keep that in mind and stay a distance away. All 6 recon enemies must be defeated in order for their unit to "retreat" instead of being "victorious".
5:Repair sessions: Between battles, areas are continuously subject to long rounds of repair sessions. Usually when a fort reaches a certain amount of damage (around 1~45 damage) units will be sent out to stand guard and repair it during an event less campaign (the unit will be "victorious" upon finishing, but no actual campaign battle begins). At these times the fort regains 10 fortifications per tic. The unit can (and usually seems to) repeatedly respawn over long drawn out hours to repair a fort until it is at full HP once again. Occasionally units will spawn and stand guard at forts even at full fortification. The reason I include this as a type of battle is that it does award influence (see below). What's more, it seems to be a kind of Campaign filibuster that bleeds small gains in influence out of an area.
Zone Influence, Victory or Retreat:
Influence decides who owns the zone for the week. As Kuno pointed out, the strongholds become subject to attack when all zones are owned by a single army. If the allies control all zones in their region, the beastmen stronghold will become subject to campaign battles, and vice versa. While allied cities are subject to campaign battle they may be under constant attack, making NPC teleportation, Campaign Ops, Sigil, and other functions very impractical. It is not yet known what occurs if beastmen control an allied city. It is speculated but not yet known that unique Campaign Ops offering BC awards becomes available if the allies can either own all regular zones in it's region, or take over the beastmen stronghold.
Zone influence depends upon battles being won or lost, each unit being victorious or retreating. This needs emphasis because some seem to think that lowering the forts HP to 0 is the ultimate goal which is not true at all. Repair session "victories" do seem to count towards influence, as I have witnessed repeated rounds of fort repair slowly diminish a nations influence. It appears as though influence points can be gained from both forcing opposition into retreat, and defeating an enemy leader. Both award a point of influence. However, influence points during a single battle seem to cap at two points per entire battle. For example, if a battle lasts for hours, with multiple units joining, enemies retreating, and leaders being defeated, the award for the most successful side will still be the modest one or two points instead of a large sum of influence. This is roughly what I've observed so far but I'm still confused on how influence is decided across long complex battles.
Morale and Prosperity:
Seems to affect overall strength of the NPC's or enemies for an army and also how easily that army can retreat from a battle. Presumably lowered when a leader is defeated, or a unit of their own retreats. If leaders dying does effect morale, a good place to start for nations having a rough time is to repeatedly defeat the weakest NM of a region. Alternatively, tougher leaders can simply be kited to allow for the regular mobs to be defeated easier and hopefully eventually result in retreat. Supposedly, beastmen are subject to lower morale by means of defeating appropriate beastmen in their regions zones. I am not so sure if this true or just a rumor.
Prosperity is separate and effects funding for things like technology, and weapons development. With high prosperity and the right weekly policies things like Mantlets, and Belfries are encouraged.
Resources:
Temporary items available to you from an NPC. They appear to be provided directly as the result of Campaign Ops. The process starts with Resource Procurement, obtaining raw supplies. Then onto Supplies Manufacture to have the items synthesized. Last the Supplies Transport Ops deliver the actual items to the forts where players can use them during battles. 1 resource is literally equal to one item for one person to receive.
Fortifications:
While attacking a fort, you may notice that once the HP reaches 50% instead of declining it will refill. Presumably this is to reinforce the idea that the forts HP bar is impractically too large to use a single bar. So instead, one half of an hp bar = 1 fort point. 150 HP units is the default standard for a fort. Fortifications can be added above that by completing the "steel resolve" Ops to a maximum of 300. After a campaign tally the beastmen can inherit the higher level fort HP from when it was player owned. In addition to players attacking a fort during battle, recon NPC's can sabatoge a fort with bombs, as well as players doing the "Slaughterhouse" Op. During fort repair downtime they regen at 10 fort hp per tic. Recon units can also restore a greatly damaged fort for huge amounts. If a fort takes a great amount of damage in one battle it's possible for the owners to retreat (not sure how much is required). When a fort reaches 0 fortification it is said to reduce the maximum HP and the fort once again regains full HP albeit at the lowered cap.
Unanswered Questions:
Red zone bars: What the fuck are they?
Physician NPCs: What causes them to cast higher/lower tier spells? (Simply # of zones controlled or is it the zone they appear in?)
How much fort damage is required before a unit retreats?
How much do forts repair from recon units?
How much do bombing units damage forts?
How long are the mobs/npc respawn time?
Fact or myth, engaging enemies while under fort repair can cause campaign to start? (has no effect in my experience)
Fact or myth, defeating normal enemies can lower morale?
Does defeating regular beastmen NM in strongholds lower morale?
XI Wiki


It's hard to draw anything definite from Campaign however because of the complex nature of it, which is why I posted here though to see if other people see the same or different things.
