BACK 4 BLOOD

Back 4 Blood is a thrilling cooperative first-person shooter from the creators of the critically acclaimed Left 4 Dead franchise. You are at the center of a war against the Ridden. These once-human hosts of a deadly parasite have turned into terrifying creatures bent on devouring what remains of civilization. With humanity's extinction on the line, it's up to you and your friends to take the fight to the enemy, eradicate the Ridden, and reclaim the world.
Cooperative Campaign
Fight your way through a dynamic, perilous world in a 4-player co-op story campaign where you must work together to survive increasingly challenging missions. Play with up to 3 of your friends online or go solo and lead your team in battle.

Choose from 8 customizable Cleaners, one of the immune survivors, and a range of lethal weapons and items. Strategise against an ever-evolving enemy bent on your total destruction.
Competitive Multiplayer
Play with or against friends in PVP. Switch between playing as a Cleaner with special perks and the horrific Ridden. Both sides come with unique weapons, abilities, and specialties.
Extreme Replayability
A new "rogue-lite" Card System creates different experiences each and every time, putting you in control to craft custom decks, roll different builds and undertake more demanding fights.

The Game Director is constantly adjusting to player actions, ensuring exciting fights, extreme gameplay diversity, and tougher legions of Ridden - including mutated boss types up to 20 feet tall.
MATURE CONTENT DESCRIPTION
The developers describe the content like this:

This Game may contain content not appropriate for all ages, or may not be appropriate for viewing at work: Frequent Violence or Gore, General Mature Content