User blog comment:B214/Question and Answers 4/@comment-4547267-20141128000402/@comment-23853100-20141128095821

No one said a word that Ise will lose his perverseness, so you don't need to go around trying to insist Ise will become non pervert. Plus no matter how perverted a guy is, there'll reach a point in life where he'll stop being a pervert. Once Ise gains experience with females, e.g. love, sex, marriage life, family responsibility, children etc, even Ise's perverted nature would reduce.

Being perverted is one thing, but being unable to mature from perverseness is another thing. You can't have sex if you keep fainting over the smallest issues after all. Look at Ise, in the beginning of the series, he gets excited and nosebleeds over the smallest issue like just seeing Rias naked, now even if all the girls are naked around him, Ise is fine. Trying to spend time peeking, stripping women and talking to breast isn't going to make Ise a non-virgin after all. So no matter how, Ise would still have to lose or control his perverted nature sooner or later. Like B and Gary said, as long as Ise keeps his love for breast, the Oppai Dragon is immortal.