: Halo 4 released in 2012, and it seemed like it took the entire studio to work
: on that game, so how is Halo 5 coming out two years later? With a
: complete campaign, multiplayer, and surely more since they understand the
: demand of quality content from this fanbase? Main Halo titles took 3 years
: or more unless I'm mistaken.

Halo 1: 3-4 years in development (1997?-2001)
Halo 2: 3 years (2001-2004)
Halo 3: 3 years (2004-2007)
Halo Reach: 3 years (2007-2010)
Halo 4: 3 years (2009-2012)

Releasing Halo 5 just two years after Halo 4 would be stretching it. I don't see how they can release a quality product in that little time, unless a significant amount of the work was done before Halo 4's release. I can imagine that a significant amount of the story was written long ago, since 343i seems to have more of a long-term vision for the story than Bungie ever did.