http://images.wikia.com/masseffect/i...on_content.jpg
Data mining through the latest patch has found that 4 of the 16 characters that are added by Retaliation are Volus.
Volus Adept
Volus Engineer
Volus Sentinel
Volus Vanguard
... I AM A BIOTIC GOD!
Oh, missing from the picture is the Quarian Marksman (a Male Quarian Soldier) and the Turian Havoc (Soldier) and Ghost (Infiltrator), as well as the Collector AR.