User blog comment:B214/Question and Answers 2/@comment-4547267-20140227014943/@comment-24098614-20140227023359

You have to put Kuroka in S class as well, and when it comes to seduction and sexiness she is "SS" class by herself because she made Issei stutter and sweat like nobody else's business, and Issei better be thankful that Koneko is there to keep control of  her sister because I consider Kuroka like a Great White Shark going in for the kill because Issei might brag that he is the Harem King but Kuroka makes him look like a schoolboy because she made him look like that in Volume 11 even Akeno can't hold a candle towards Kuroka in this dept. I also put Gabriel in the S class as well because she is the most beautiful woman in Heaven, and she rightfully deserves to have this title. The problem is that this series has so many beautiful women that is hard to put a rank on all them if you were to classify them fairly.