You know... I don't think I've ever seen anyone mention this but it's part of a joke me and my best friend have about DMC4 which is... It seems to be based on another game of Capcom's that was also the 4th in the series.
Nero=Zero Kyrie=Iris Credo=Colonel
Even the plot is somewhat similar.
George Carlin~ Inside every cynical person, there is a disappointed idealist. My Father~ Failure is ALWAYS an option... but giving up is not.