Rias Gremory is the president of the devil's clan. She don't take her job as seriously as all the other leaders. (Due to slacking off and preying on young men) But when she does, she is a force to be reckoning with. And that mentality has cause a BIG scandal that her and a few people only knew (A little context to it, her scandal is one of the main reasons of why Part 2 even exist in the first place. Her daughter (Who was 10 or 11 at the time) and husband was no doubt was involved with it.  Her husband is missing (She knows the real truth of his disappearance) and her eldest daughter working for the Main villain of part 2. (Yes that is another scandal that she and her family is desperately is trying to hide from the public.) To me, Rias is REALLY back down into a corner in this series and if a "Certain" man founds out what that scandal is then their is no doubt that herself is basically dead. 

Director Note: So I should say that since Rias is from the devil race that she has a very long lifespan.  In my eyes, she has a body in her early thirties to mid thirties. Her voice should be kind of causal and a little deep. But when serious matters upon her that is when she is at her chilling side.