User blog comment:Jopjopjop/Volume 18 Spoilers/@comment-213.120.234.154-20140910170309/@comment-24502975-20140910193820

One thing I'd like to point out: Ise becoming less perverted is a GOOD thing. He's still the same breast-loving Devil we all know and love, but perverted thoughts are not occupying his attention 24/7 now. He's maturing, shaping into a highly-respectable High-class Devil(probably by the end of this arc). And that's wonderful. (Like Kuroka said in v15, his mind has to catch up to his strength).

As for Rias, have you read Life.0 of volume 18? If you're waiting to read the entire volume at once, I urge you to read just this one part now. Their relationship is getting much stronger, not weaker, while at the same time greatly improving his relations with all his other girls as well(one of the many reasons I love this arc, next to Ise finally being a powerhouse who doesn't need to rely on luck or breast-power to win).