Building on the M. Night Shyamalan cinematic universe, Split introduces us to Kevin Wendell Crumb. He suffers from DID, but not just the movie style multiple personality silliness. This is going into the realm of superhumans, so when James McAvoy jumps from personality to personality (blog post) and goes on and on about "the beast" and how it will do (blog) oh so much damage... yeah.. things get (blog) a bit more complex than you usual kidnapped horror...
Source: Split Movie Review - Decker Shado