I have a rule that the higher the maturity rating the more immature the content in a game tends to be. Yes, there are exceptions but for the most part it tends to ring true.
Capcom has had a long standing policy of no nudity, damn near no cussing, and most definitely no sex or nudity. I think Shinji Mikami was the only one who broke those rules. Anyway, I remember that there was an interview with some staffers from NT and they said that Capcom very specifically said 'no nipples.'
On the other hand DMC4 had no blood. Everything was green and... boring. DMC1 had real blood but the rest were so tame. Sand, green liquid and I think neither DmC nor DMC2 had blood, either. There was that scene with baby executioner, but that game did have a mature rating, but still, not a whole lot of blood during combat. I hope they man up a little on that.