Near the beginning of Chapter Five, Bayonetta threatens to kill Luka who tried to convince her that she shouldn't because it would break the hearts of four girls. The girls names are Claire, Trish, Silvia and Ammy. All of which are characters from previous titles that the team worked on when they worked at Capcom.
Claire being Claire Redfield from Resident Evil. Trish being a character in Devil May Cry, Silvia also being a character from Viewtiful Joe and Ammy being short for Amaterasu from Okami.