According to a report on Fustible (via Coming Soon), Warner Bros. has quietly registered a whole host of domains with brand protection company MarkMonitor. Based on the registrations, possible titles now include "Man of Steel Battle the Knight," "Man of Steel Beyond Darkness," "Man of Steel Black of Knight," "Man of Steel Darkness Falls," "Man of Steel Knight Falls," "Man of Steel Shadow of the Night," "Man of Steel The Blackest Hour," and "Man of Steel The Darkness Within."
What's interesting about these domain names is that, per Warner Bros. originally statement, they are very much "Man of Steel" sequel titles. The title hasn't been drastically altered (or reverted back to "Superman"), although these titles could really be for anything connected to the movie, including but not limited to iPhone apps, video games, or a line of decoratively scented bath candles. Only time will tell.
The Zack Snyder movie, which stars Henry Cavill as the Man of Tomorrow and Ben Affleck as The Dark Knight, alongside Amy Adams, Diane Lane, Laurence Fishburne, and whoever is playing Wonder Woman and The Flash, debuts on July 17, 2015.