Turtle Rock Studios released a new trailer for Back 4 Blood this week to focus not on the card system but on the main characters themselves: The Cleaners and the Ridden. The Cleaners are the main human characters in Back 4 Blood that people will play as while the Ridden are the zombies that swarm the streets. No updated release date was given in the new trailer, so we can still expect the game to be releasing on October 12th assuming nothing changes.
Most zombie games will give their factions different names other than just "zombies" and "survivors" nowadays, and as afar as nicknames go, "Ridden" and "Cleaners" aren't too bad. The infestation of the infected needs to be cleaned up somehow, so it's up to the main characters introduced in the trailer to assist with that.
You've likely met a few of the characters if you played during the technical test a couple of months ago, but by now, more characters have been introduced. The number of Cleaners confirmed for Back 4 Blood now totals eight different characters, a number that gives everyone on a four-person team at least two options to pick from so that they're not stuck with the last character available. Those characters consist of Walker, Doc, Karlee, Jim, Hoffman, Evangelo, Mom, and Holly who all have different specialties outlined in the trailer such as better support for the team and higher damage using different types of weapons.
Then there's also the Ridden, the infected creatures in Back 4 Blood better referred to simply as the zombies. From the test before, we saw a couple of different kinds of these special versions of Ridden. Ones showcased in the trailer include the Ogre, Snitcher, and Hag. Like the Cleaners, they've got traits that separate them from the normal zombies players will come across, and they're part of the card system as well since it's not guaranteed that players will come across each kind of Ridden during a round.
Following its delay from March, Back 4 Blood is currently scheduled to release on October 12th for the PlayStation 4, PlayStation 5, Xbox One, Xbox Series X|S, and the PC via the Epic Games Store and Steam.