User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-82.40.154.8-20131227140129/@comment-16281343-20131227154748

1.) Issei is active in foiling the actions of the KB. So if they want to create a replica of BG, they can since they can collect huge amounts of data with all those confrontations. And take note, there are also FAs in KB, so they have the technology to create artificial SGs.

2.) Their memories are altered by Rias to adapt in the changes in their house. And in the part of them accepting the girls, they are okay and happy with this because before the girls arrived in Issei's life, they have resigned theirselves on them not having grandkids. But now, not only the girls around Issei are all beautiful, they don't have to be bothered on them not having grandkids in the future.