Dante (as well as himself from Viewtiful Joe) -> Drew Coombs

Trish and Eva (Dante's Mother) -> Sarah Lafleur

Nelo Angelo (Vergil) -> David Keeley

Mundus -> Tony Daniels

Phantom and Griffon -> Howard Jerome

Young Dante and Young Vergil -> Jonathan Mallen

Dante (as well as himself from Shin Megami Tensei) -> Matthew Kaminsky

Lucia -> Francoise Gralewsky

Matier -> Flo Di Re

Arius -> Sherman Howard

Dante (as well as himself from Marvel vs CAPCOM 3) -> Reuben Langdon

Vergil (as well as himself in Ultimate Marvel vs CAPCOM 3) -> Daniel Southworth

Lady -> Kari Wahlgren

Enemies and Most Bosses -> Larry Leong

Arkham and Jester -> Adam D. Clerk

Nevan -> Mary Elizabeth McGlynn

(There was a Russian voice cast as well. Cannot find the information for who voiced as them in Russian.)

Nero -> Johnny Yong Bosch
Japanese voice - Kaito Ishikawa

Dante -> Reuben Langdon
Japanese voice - Toshiyuki Morikawa (Also voiced as him in Ultimate Marvel vs CAPCOM 3 and the Project X-Zone series)

Vergil -> Daniel Southworth

Japanese voice - Hiroaki Hirata (Also voiced as him in Ultimate Marvel vs CAPCOM 3 and the Project X-Zone series)

Kyrie -> Stephanie Sheh

Credo -> T.J Rotolo

Sanctus -> Liam O'Brian

Agnus -> T.J Storm

Lady -> Kari Wahlgren (Original DMC4)
         -> Kate Higgans (DMC4: Special Edition)
Japanese voice - Fumiko Orikasa (Also voiced as her in the Project X-Zone series)

Trish/Gloria (as well as herself from Marvel vs CAPCOM 3 ;)) -> Danielle Burgio
Japanese voice - Atsuko Tanaka

Enemies and Most Bosses -> Larry Leong

Echidna -> Mary Elizabeth McGlynn

(There was a German voice cast as well. Cannot find the information on who voiced as them in German.)

Dante -> Reuben Langdon

Japanese voice - Toshiyuki Morikawa

Patty -> Hilary Haag
Japanese voice - Misato Fukuen

Morrison -> Rob Mungle

Japanese voice - Akio Ohtsuka

Lady -> Melissa Davis

Japanese voice - Fumiko Orikasa

Trish -> Luci Christian

Japanese voice - Atsuko Tanaka

Sid -> Chris Ayres

Japanese voice - Nachi Nozawa