The Back 4 Blood card system is perhaps one of the most important mechanics in the entire game. Adding a bit of a roguelike spin to each run, you must choose random cards from a pre-established deck at the start of each act to build out your character and prepare for what lies ahead. 

For this reason, there are probably some important things you should learn about it before diving in. Back 4 Blood requires a lot of cooperation so learning the basics is a must. Here's what you should know about the card system.

Back 4 Blood Card System Explained – Best Cards

Active Cards vs. Corruption Cards

Active Cards are anything you opt to add into your decks that help you get to the end. These are what you plan for and are important to keep track off. You want an idea of your build before you commit to the map and stacking your deck is a great way of conceptualising it. 

Corruption cards offer a similar system but generally through debuffs. They are split into a few main camps all doing very different things. The first type of corruption add new special infected in the form of Ridden and Mutations.

They create entire new zombies or add special abilities and stats to current ones. Generally, this adds a passive bit of extra difficulty to each act. After this, you will find the challenges. They will task you with completing special objectives in exchange for fancy new items.

If you want to earn some extra copper and supply points and feel up for a new challenge, these are worth trying. Events are another type of corruption card that dynamically affects levels.

It may add fog that is hard to see through, take the power out leading to alternate routes or high security areas leading to lots of alarms. Generally, these aren't worth taking if you can avoid them. Lastly, you take a corruption card at the act finale that sets a new piece of the story in motion.

Having you complete a brand new task, it's a good way of keeping runs feeling fresh. As you won't know what this challenge is, you can't always plan your route and build around it. 

Back 4 Blood Card Types

There are four central types of card in Back 4 Blood. Reflex tends to affect your technical skills, Discipline is all about preparedness, Brawn is about your toughness and Fortune tends to play into RNG or money. 

Each card is then further labelled with Offerns, Defense, Mobility or Utility. These categories will greatly help with your build, pointing you in the right direction. Once you've figured out what each card is supposed to do, it's time to build a deck. 

Solo Decks

There are three central decks you can create and they are all for different modes. As you might expect, Solo Decks are created for Solo campaigns. This means you should pick cards that complement a lone wolf playstyle.

You will have teammates but they're all bots so you are often best off letting them play support while you provide fire. After all, it's harder to leave exploration and tactics in the hands of a machine.

Unfortunately, you cannot earn any gear in solo yet but all cards are unlocked from the get go. This means you can go through them and look right now.

Campaign Decks

The campaign is the classic mode and will likely be your most played game mode in Back 4 Blood. Having you go through a handful of acts, you must play alongside friends, strangers or bots to complete them. Even if you don't succeed, you will earn supply points that are used to earn new cards. 

Swarm Decks

Swarm is Back 4 Blood's PVP mode, having one team of cleaners and one team of ridden take each other on in a deathmatch. Where cleaners use their cards to even the odds, the ridden use a leveling system that lets them get stronger throughout the match. 

What Are The Best Back 4 Blood Cards?

There isn't a straightforward answer to this question. It all depends on your choice of cleaner, your build and what role you play in your team.

Cards like Avenge the Fallen give huge buffs as people go down and Down in Front give extra damage and immunity from friendly fire when crouched but not all cards are quite as general in application. 

If you're playing a melee heavy build, you could opt for Mean Drunk and Spiky Bits that disables sprint and cuts down on ammo capacity whilst giving 100% extra damage from melee. 

For a more speedy build, going for Widemouth Magwell (higher reload speed and lower damage resistance), alongside Run and Gun and Olympic Sprinter (better sprint at the cost of damage resistance) will leave you zooming past the competition. 

It seems that the best choice is not to pick the best cards but design the most efficient build. Have a central idea in your head as you pick your cards and pick options that compliment it. Not only will this encourage committing to a more efficient playstyle but it leaves room for creativity. 

If you can rope in three friends, plan your paths, pick your builds and stick to a playstyle, you may just make it out alive. One could focus on healing, one could work on team buffs and the other two could go for heavy damage.

Remember, whilst there are 15 potential spots in your deck, you don't need to fill them all. Just pick what you need and don't get greedy – a zombie could get you first. 

Related: Back 4 Blood | How to Unlock All Characters, Cleaners