Though the demo was just released with Ninja Gaiden 3, intrepid hackers have already blown the Dead or Alive 5 code wide open to take a peek at what may be hiding below the surface. While there aren’t any full character materials, a NeoGAF user by the name of Sectus discovered a wide array of alternate costume data, which may hint at the final cast selection. The full list of spoilers has been posted below the following image.

It would seem much of the Dead or Alive 4 cast is returning to this installment, along with new characters Mila and Rig. Also, Virtua Fighters Sarah Bryant and Pai Chan will be joining Akira Yuki as crossover guests. The full list is as follows:
Pai
Sarah
Akira
Mila
Rig
Bayman
Hitomi
Christie
Brad
Lisa
Eliot
Ayane
Lei Fang
Hayate
Kokoro
Bass
Leon
Helena
Gen Fu
Kasumi
Hayabusa
Jann Lee
Tina
Zack
Alpha-152

Source http://shoryuken.com/2012/03/22/rumor-entire-dead-or-alive-5-cast-discovered-in-demo-code/