Factions (sometimes referred to as elements) are the 6 primary groupings of zombie cards in Zombie Battleground. The 6 factions are Air, Earth, Fire, Life, Toxic, and Water. Each faction is represented by one or more overlords, and has a set of zombie cards which belong to it.
A deck of cards must be based on one of the 6 factions, which has several impacts on deckbuilding and gameplay.
Faction Strengths and Weaknesses
Each faction is designated as strong against one faction and weak against another. This designation is only marginally present in the card design of each faction (with only a small handful of cards explicitly gaining additional power when played against the corresponding "weak" faction), and is mostly important during deckbuilding. The image to the right depicts the circle of strengths/weaknesses.
When creating a deck of cards to play with, the first decision a player must make is which faction the deck will be based on. This choice determines a number of factors about the deck.
Each faction has a set of abilities which can be used periodically throughout a match. Some of these abilities can only be used on ally zombies from the same faction as the overlord. See the overlord page for a list of the available overlord abilities.
When building a deck, there is only one restriction placed on which cards can be included: a deck cannot contain any cards from the faction which it is weak against. For example, when building a Fire faction deck, no cards can be used from the Water faction because the Water faction is strong against the Fire faction.
Goo Overflow Cards
While a deck can include cards from any faction other than the one the overlord is weak against, cards which make use of the Goo Overflow system will only activate their overflow abilities when played by the overlord of the matching faction. For example, Modo is a card from the Fire faction with an overflow ability. While it can be included in any deck other than one based on the Toxic faction (because Fire is strong against Toxic), its overflow effect will only activate when played in a Fire faction deck.