User blog comment:Mnzombie/Issei's Peerage/@comment-70.66.66.212-20131004173825/@comment-9339850-20131004182122

Devils always remain the piece that they were reincarnated as, so no matter if a devil is able to become high-class and have their own peerage, they still have to follow the orders of their master whenever they are summoned

Azazel and Rosswiesse have explained to Issei that having a harem for his peerage probably wouldnt be good if he wants a strong diverse group. And he has started to understand this as well.

As for Le Fay and Kuroka, well if he takes Kuroka he can no longer take any other bishops like Ravel or Asia because she is worth 2 pieces. And it wont be a long while or will take a huge event for Le Fay's association with Khaos Brigade and Vali's team to blow over.

And Irina will never Fall from her Angel status; Mainly because, why have more than 1 Fallen Angel in his harem. The author has said that he wanted Issei's harem to be diverse and have girls with different backgrounds, which is why Irina Falling is a very big strech