IGN has a video series that exclusively goes behind the scenes with Dead or Alive 5. IGN has discussions with various members of Team NINJA talking about coming up with the Fighting Entertainment that is Dead or Alive 5 and what they have been doing for the past seven years. You might also catch some hints at things from various monitors showing off the game and the developers working on them. For example, I saw a Bruce Lee outfit on one monitor so you can probably guess which character has such a costume.
They have released part 1 of the series and I honestly am looking forward to seeing the follow-up parts:
Part 2 has been released!
Part 3 has been released!
Part 5 has been released!