I dont think the pure devil can say too much anymore. About Rias x Ise i mean ise just save them with the help of GR. Also the whole Gremory family it's ok with this now ,hell they even try to push them to marry. No to mention they already think Ise part of their family+ lucifer (rias brother ) already think about Ise like his own little brother. And we can't forgot that Ise already have link with at least other 2 devil family . If then we count that he is friend with ophis...yeah i wonder if they will still think about the whole Half-breed children deal.
