Resident Evil 6 will let players take control of a J'avo monster to hunt down Leon, Chris and the other do-gooders in a new online mode called 'Agent Hunt'.
The mode is detailed in the latest issue of Famitsu (via Andriasang), which says certain stages can be opened up to Agent Hunt play once the game is completed.
In these missions other players can invade your game and take control of creatures to bring down the Agent. It also allows multiple players to band together and supports voice chat.
The Agent will be notified when another player assumes control of an enemy, but won't be told which creature is under player control. Sounds very Dark Souls-ish to us.
Her single player only scenario will be playable once Chris, Leon, and Jake's scenarios have been completed. Ada will be armed with a crossbow and has time bombs.