Onslaught is a multiplayer DLC for Resident Evil 6 that was released alongside Survivors and Predator.
In Onslaught, two players try to survive waves of enemies sent by each other. Though in the same stage, the players are isolated from each other. The player can stack up the combo up to 30 and if done successfully, this will send all 30 the enemies that have been killed to the opponent.
An "Offense" mechanic which is unique to this mode can be used to power up the character, killing enemies with a melee attack and sending enemies to the opponent early via the use of a taunt will increase this Offense number, which stacks to up to 300%. Taking damage will decrease the Offense, and completing a full 30 combo will reset it completely. At 300%, players will be able to kill enemies, including bosses, very quickly with any weapon type.
Enemies in Onslaught by default are aggressive and spawn in great numbers. Mutated enemies such as the Glava-Begunats tend to spawn quickly. Sub-bosses such as the Ubistvo can be sent to your opponent to further worsen their situation and also decrease their chances of survival.
Enemies that are sent to you are noticed by their grosteque slime covering them. In addition to pressurize the player, J'avo that have been killed in a mutated state will stay that way when sent by the opponent. The match ends when one of the players has been overwhelmed with the last man standing being the victor. If both of the player survived, the person with the highest score wins the match.