True. And enemies in DMC4 do seem to correspond to these characteristics:
1) Fire: Berial, Basilisks
2) Air: Angelos
3) Water: Cutlasses
4) Ice: Bael/Dagon, Frosts
5) Earth: Assaults
Yeah but Angelos and Cutlasses are "artificial" demons, created thanks to Agnus's research. So they don't come directly from Hell. I think that Mephistos should be linked to air, while water... I don't know.