Metal Gear Solid Online is the multiplayer component of, and apparently it will support up to 16 players on PC and next-gen consoles.
That's according to the game's Japanese website (spotted). The online mdoe is included with all copies of The Phantom Pain, and sets two teams against each other utilising the series' trademark mix of stealth action gameplay.
Hideo Kojima showed a brief snippet of online play off atlast year. It's not entirely clear what the range of objectives are, but at one point Snake hops into a kind of primitive ATST with a minigun and starts blowing everything up, so there's that.
You can also use his nifty camouflage device to fool other players. At a developer session at EGX Kojimathere would be a home-building aspect, as well as cross-platform support for tablets and smart phones.
Metal Gear Solid V drops on September 1, for PC and consoles.