In the end I'd look forward to an epilogue for this arc that focuses on that part. Can easily just make him yet another person helping out at Luvia's place and just mess with the paperwork so he's also part of that family. At this point it'd make for a "what the?" moment, but not the first one. Miyu already has the same birthday as Illlya and then you can just toss in her coincidentally having a brother near identical to Illya's brother
. At some point the weirdness should just become something that everyone around Illya just nods and accepts.
Was nice to catch up on the last couple chapters. In the end Illya did get her way in being able to save Beatrice (at least it appears to be the case). At least she shouldn't be a problem going forward so long as they grab that card from her.
Bigger issue though is that rogue Sakura. No chance she isn't coming back into the picture. And so long as she doesn't toss that fake Rule Breaker she might still cause some serious problems later on. Sadly not everything is going to go according to plan. Though I will say that Serenity Miyu was kind a cool move to go with the assassin card.