DMC4 bosses back-story

[slapsus]

Does anyone know anything about the bosses in DMC4 like what they were doing, their origin and quarrels with Sparda in the past or anything similar?... I'm mainly talking about Berial, Echidna and Bael&Dagon 'cause they are the only bosses in DMC4 that seem to have lived 2000 years ago.

 

[Sparda™]

It is said during the cutscene Berial against Nero that he claims to have visited the human world two-thousand years during the time of Sparda, and never met any human like Nero except for "him" (who may be Sparda).

As for the other bosses, they don't seem to mention anything.