The Alliance War in Cyrodiil involves seizing, holding, and controlling the resources of massive strongholds, utilizing siege weapons, taking Elder Scrolls, and crowning an Emperor for the respective Alliance. Cyrodiil also offers PvE content, such as repeatable quests found in towns, exploring caves, crumbling towers, and Ayleid ruins, and finding valuable crafting materials that can only be obtained in Cyrodiil.
Players may enter the province and engage in PvP once they reach level 10, where they will be assigned to a Campaign and access to Cyrodiil from a safe location that enemies cannot enter. Players are boosted to the stats of a typical Level 50 (they are not boosted in the case of the player being Level 50) so all players are given an equal chance, however higher level players will still have more of an advantage as they will have more skills and passive buffs than lower levels. 
A Campaign consists of a group of players battling for control of Cyrodiil for a set period of time. Campaigns can last for 3 months or longer, and multiple Campaigns in Cyrodiil occur at the same time but players can only see other players from their own campaign due to the megaserver phasing technology. Players can assign themselves to 2 campaigns at a time, a home campaign, in which players receive the full bonuses of being in a campaign, or a guest campaign in which players can assign to if they just want to do PvP. Players are be able to visit other Campaigns at a cost of 15,000 Alliance Points. During a Campaign, an Alliance’s performance will affect bonuses players can receive across the game (not just in Cyrodiil). For example, having an Emperor on the throne who is in your alliance, will give all players assigned to that campaign +5 extra health per level, so at Level 50 players will have +250 health.
At the end of a campaign, players receive rewards depending on whether an Alliance came in 1st, 2nd, or 3rd for that campaign duration, with 1st obviously being the highest reward tier. Cyrodiil will always remain open, even at the end of a campaign, and Alliances do not lose any ownership of their keeps. The only thing that changes at the end of a campaign is the Alliances scores, which get reset to 0.
Each campaign can have 2000 players in Cyrodiil at once, with the client being optimized for 200 players on-screen at one time.
Alliance wide bonuses in PvP and PvE are awarded for taking and maintaining the territory of keeps. There are 18 keeps in total, with 6 keeps owned by default (but can still be taken) in each of the 3 alliance territories. Keeps are linked together in a transit line. If an Alliance holds several linked keeps, its members can fast travel from one to another using a "Transitus Shrine", unless that keep is under attack or enemies control all 3 of the keep's resources.
Every wall, gate and even the roof in keep is destructible. However, once a keep is taken it stays in the condition in which it is inherited, meaning that any walls and gates that were destroyed or damaged will need to be rebuilt or repaired. Masonry and woodworking kits can be purchased to help repair them more quickly. There are two flags in a keep which must both be held by the same Alliance to officially capture it.
The three resources around a keep are lumber mills, farms, and mines, which fuel its upgrade process. Lumber mills help make keep doors stronger and allow them to repair themselves automatically. Farms make keep guards tougher and stronger, and mines help reinforce the walls, making them harder to destroy and allowing them to repair themselves over time as well. Taking control of resources around keeps also shuts off various patrols in the vicinity. There are capture banners at each resource, and resources are captured independently of keeps.
Towns and VillagesEdit
The citizens of towns in Cyrodiil are neutral towards player characters, but guards from the Alliance that holds nearby keeps will patrol the streets. The way citizens react to players varies depending on whether or not they belong to that Alliance. Each town offers different repeatable quests that reward players with gold and experience.
The title of Emperor is given to the player with the highest score while their Alliance controls all of the 6 keeps surrounding the Imperial City (Chalman, Aleswell, Ash, Roebeck, Alessia and Blue Road). Once crowned, the Emperor will receive an entire skill line which can only be gained through achieving Emperor status. Powers include being able to make siege more effective, being able to knock down walls quicker, doubling their health, magicka and stamina and having reduced Ultimate Ability costs. An Emperor is dethroned when their alliance loses all the keeps necessary to crown an Emperor. The dethroned Emperor will still keep their skill line and given the title of "Former Emperor", although the abilities in it become much less powerful.
Alliance Points can be used to purchase armor, weapons, advance in several skill lines specific to Cyrodiil, join a new campaign, or purchase siege weapons. The highest amount of Alliance points are awarded for participating in keep battles and contributing to the keep's capture.
Siege Weapons are used by players to break down walls, smash open the doors of keeps, collapse the keep's roof and obliterate the armies of their opponents. Trebuchets (Firepot and Iceball), catapults (Meatbag, Oil and Scattershot), ballistae (Fire Ballista, Ice Ballista, Lightning Ballista), flaming oil and battering rams are available to use, and they can be obtained and constructed by anyone that has the Alliance Points to purchase them. Rams are mobile, and ballistae, catapults, flaming oil and trebuchets can be packed up after they’re deployed so that they can be repositioned for further, more tactical uses. If an enemy siege operator is killed, players can set the weapon on fire and it will get destroyed very quickly, however players of the alliance owning the weapon can douse the flames and take over the role of operator.
Forward Camps are special types of siege equipment. They are the most expensive siege equipment, costing 7,200 Alliance Points to purchase. They are also, however, among the most useful. When a Forward Camp is set up, any dead player from the owning alliance can respawn at the camp and join their alliance in battle. However, Forward Camps cannot be placed in the vicinity of an enemy keep, outpost or resource, nor can they be placed within a certain radius of another friendly camp. They also have a limited number of respawns, which is 20 players per camp. Players can set up camps in a keep their alliance controls, but this is only useful when the keep is under attack. Enemy players can set camps on fire like all other siege weapons.
Elder Scrolls are artifacts of immense power which give Alliance wide bonuses. Each Alliance has two Elder Scrolls by default and may only receive their bonuses while they are kept in special strongholds or keeps held by that alliance in Cyrodiil. Enemies from the opposing Alliances can break into these strongholds and take the Elder Scrolls back to their own strongholds and keeps.
- Eastern Elsweyr Gate
- Northern High Rock Gate
- Northern Morrowind Gate
- Southern High Rock Gate
- Southern Morrowind Gate
- Western Elsweyr Gate
- Arrius Keep
- Kingscrest Keep
- Blue Road Keep
- Farragut Keep
- Fort Dragonclaw
- Chalman Keep
- Fort Aleswell
- Castle Alessia
- Drakelowe Keep
- Castle Faregyl
- Castle Roebeck
- Castle Black Boot
- Castle Bloodmayne
- Fort Ash
- Fort Warden
- Fort Rayles
- Castle Brindle
- Fort Glademist
- Nikel Outpost
- Sejanus Outpost
- Bleakers' Outpost
- Temple of Chim
- Temple of Ghartok
- Temple of Alma Ruma
- Temple of Mnem
- Temple of Ni-Mohk
- Temple of Altadoon
- Gate of Chim
- Gate of Ghartok
- Gate of Mnem
- Gate of Alma Ruma
- Gate of Altadoon
- Gate of Ni-Mohk
- The Elder Scrolls: Arena
- The Elder Scrolls III: Morrowind (Mentioned only)
- The Elder Scrolls IV: Oblivion
- The Elder Scrolls V: Skyrim (Mentioned only)
- The Elder Scrolls Online
- ↑ October 18, 2012. The Elder Scrolls Online Tamriel, Now and Then – Places
- ↑ 2.0 2.1 2.2 2.3 2.4 The Elder Scrolls Online The Alliance War
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 March 28, 2013. The Elder Scrolls Online Conflict in Cyrodiil, Part 1
- ↑ 4.0 4.1 4.2 4.3 4.4 September 9, 2013. The Elder Scrolls Online Ask Us Anything: Variety Pack 7
- ↑ July 1, 2013. The Elder Scrolls Online Do our Alliances get completely reset at the end of PvP campaigns
- ↑ January 29, 2013. The Guardian Elder Scrolls Online: How PVP allow players total control
- ↑ 7.0 7.1 7.2 7.3 7.4 August 24, 2013. Teso Elite ESO Interview with Maria Aliprando
- ↑ 8.0 8.1 Aug 29, 2013. mmohdtv The Elder Scrolls Online Interview with Lead PvP Designer
- ↑ June 28, 2013. The Elder Scrolls Online Support Will there be any fast travel between keeps...
- ↑ August 26, 2013. MMORPG.com On Guilds, Being Emperor, and Much More
- ↑ 11.0 11.1 11.2 11.3 April 22, 2013. The Elder Scrolls Online Ask Us Anything: Alliances at War