Castle Blood Automatic

Castle Blood Automatic, usually abbreviated CBA, is a popular scenario and game mode in Age of Empires II. It focuses on military; economy plays no role in the game whatsoever.

Goal
The goal of any CBA is to raze all enemy Castles. Once a player loses their last Castle, they are defeated instantly, and all their units are automatically killed and all other remaining buildings are automatically destroyed. Players cannot build additional Castles.

Starting conditions
There are always eight players playing in two teams. Every player plays with a random civilization and starts with a huge stockpile of resources (at least 99,999 wood, food, and gold). The starting Age is the Feudal Age for most civilizations. Civilizations with unique units that do not test very well on this battlefield (such as the Malay or the Vikings) start in the Castle Age. Some upgrades of later Ages may already be researched at the game start (e.g. for the Malay as their unique unit is very weak), but usually they have to be researched and are available for research once the respective Age is reached. Every player starts with a small fortress containing usually four towers (the kind of tower varies depending on the version, but they are never Bombard Towers) and a backward Gate as well as four Castles. The fortress itself consists of Fortified Walls provided the civilization has access to them. Civilizations without Fortified Walls and the Gothss start with Stone Walls. Furthermore, every player has a Blacksmith and University to research important military technologies as well as a spawn changer. The spawn changer is a tool to change the default spawn of the automatically spawned units (close, normal, or far).

As soon as the game starts, each Castle will start to automatically (hence the name Castle Blood Automatic) produce unique units (regular or Elite, depending on the civilization; for the Khmer there may be Battle Elephants instead) at no cost. The interval of the production depends on the civilization, but the most common rates are 8 or 10 seconds. For every civilization, there also is a cap at which the Castles stop creating units. For most civilizations, it is 80 units, but some have a cap of 60 or 100. The Castles cannot train any other units which is why at game start, there are only unique units to play with.

Kills and starting battles
In any CBA, kills are the means to advance in Age. There is a kill counter and usually as soon as any player reaches a 100-threshold, there is a notification for every player. Every civilization has an individual kill requirement to advance in Age. These requirements are set by the creator of the scenario and subject to discussion. An example of these requirements is shown below in the civilization table. Once the Imperial Age is reached, kills do not give any further advantages.

At game start, players usually inform themselves about the civilizations on the map (the players are always distributed identically on the map so everybody knows exactly where every player and hence civilization is located) and decide which enemy they want to engage in combat to quickly accumulate kills. E.g. a Goth player is very likely to attack a British or Maya player, and a Saracen will most likely meet a Persian as soon as they can.

Razes and Villagers
Razes are the most critical feat to achieve in a CBA as they grant access to Villagers. Therefore, getting razes as soon as possible and preventing the enemy to get razes is the top priority. The first razes are almost always the Gates of the players' fortresses as they are easy to reach. Deleting own Castles or the forward Gates results in instant defeat. Buildings that were constructed can be deleted at any time without penalty. Doing so is generally a good idea to prevent the enemy to get Villagers.

Every civilization has an individual count of razes that is required to get their first Villagers. The Britons and Mayans are notorious for needing only a single raze, the Huns and Persians are usually the civilizations that need most razes. A full table is shown below. Keep in mind that this is only an example. Once the first Villagers are spawned (Villagers always spawn in pairs), every further raze grants two additional Villagers. As soon as any player gets their first Villagers, walling the own base and the bases of the allies is top priority to prevent the enemies from getting razes themselves and to protect the own Castles. Once all bases are walled (or at least the own one), it is important to quickly build military buildings (Barracks, Archery Range, Stable) inside the own fortress and start creating military units. This is important because the units trained there do not have a low cap like the Caste units, so up to 300 (usually the cap) can be trained there.

Endgame
CBAs often end in mass battles, with walls spreading all across the map and large armies of Paladins, Heavy Camels, Cavalry Archers, and Siege Rams (note that Mangonels are usually disabled in CBA because that would give civilizations with Siege Onagers a huge advantage) fighting and besieging one another. At this point, players without Villagers are not particularly useful anymore due to their limited unit count and thus in these situations, usually the team with more 'Villaged' players wins in the long run.

Civilization table
The table shows the requirements for all civilizations. Note that this is only an example, there may be other settings on a server. The table was uploaded in June 2019.

* The Khmer in this example play with Battle Elephants.