User blog comment:B214/Question and Answers 6/@comment-185.112.105.215-20170323170829/@comment-9595671-20170323213613

It's not so much she won't be in the harem, the EX novel just doesn't fully confirm she'll be one of Issei's wives because we never saw a child that she was the mother of.

Luckily it's said Issei has atleast 20, so one of them mght be hers.