There have been some complaints after modders discovered DLC on the Resident Evil 6 disc and Capcom released new details on their post-launch plans to clear up any confusion:

"Chiming in just before NYCC (we have a lot going this year) to update everyone on some new RE6 content, and clarification on how this content is delivered. First and foremost, two free DLC items will arrive as a title update soon; No Hope difficulty mode (which is, y'know, super hard) and a co-op partner for Ada's campaign. Said campaign was meant as a solo affair for Ms Wong, but odds are you'd like to play through it again with a pal - soon you can!

Additionally, this update will make Ada's campaign available from the start; currently you must complete all three of the primary campaigns to unlock this bonus. So, a little something for those who aren't able to blaze through the whole thing in a weekend - if you're taking your time, you'll be able to access Ada's story without having to finish the others. And may I say, her campaign is pretty awesome.

Now, the clarification: some data of this update is on the disc, but said data is incomplete and requires the actual download to access. But again, free. Mercenaries costumes are residentevil.net unlocks. Simply register for the site and start earning RE points for those goodies.

Future paid DLC - like the multiplayer modes we revealed a while ago - is not on the disc. We said as much a month ago, but that point may have been lost in the shuffle.

The tl;dr version is - RE6 on-disc DLC is free, paid DLC is not on the disc.

Now let's work on those Mercenaries scores!"

Back in September, additional DLC game modes were announced. Here is the official press release, detailing new multiplayer modes:

Capcom®, a leading worldwide developer and publisher of video games, is pleased to confirm that the Resident Evil® 6 experience will be further enhanced with the release of new modes and additional content following the launch of this highly anticipated title on home consoles this October 2.

Available as downloadable content, three new gameplay modes will expand on the multiplayer elements available in the retail version and deliver new and exciting ways to enjoy the world of Resident Evil 6.

Survivors Mode takes the classic solo- and team-based versus mode and adds a twist. Get killed and you respawn as an enemy character with the ability to attack the human characters. Take down two human characters to resurrect in human form. Last man or team standing wins.

In Predator Mode, one player takes on the role of the Ustanak, the fearsome B.O.W. that stalks Jake Muller throughout his campaign, and tries to eliminate the human players. The humans’ task: stop the deadly B.O.W. in its tracks, or at least survive until the end of the session.

Choosing the human side in Siege Mode will see players protecting a single NPC, while as a member of the enemy team, players will need to eliminate that same NPC. If the NPC is still alive at the end of the time period, the human team wins.

Survivors, Predator and Siege modes will all support up to six players online and be played using maps from Mercenaries Mode.

Players will be able to track their accomplishments in these three modes alongside their main campaign statistics and compare their performance with others by registering on ResidentEvil.Net, the free online service that launches alongside Resident Evil 6.

Further post-launch downloadable content for Resident Evil 6 will include additional maps for Mercenaries, which can in turn then be used as maps for Survivors, Predator and Siege modes, plus other items yet to be announced.

Source: Capcom Unity