User blog comment:Rei Furuya/Brother and sister reunited/@comment-36009152-20181117180750/@comment-32952945-20181122200124

Totally agreed, but they deserve to see each other again happily unlike other releationship as you mentioned Guren and Mahiru and Mika and Yu. Asuramaru once mentioned he is just waiting for a chance to possess Yu completely therefore their might be a chance of him remembering everything and currently in the manga we don't know what or how is Krul doing.

And since Asuramaru is currently a demon and Krul is a vampire that kind of makes them enemies (despite being sibilings by blood) besides it's impossible for Asuramaru to manifest freely as a demon since he is sealed in sword form, unlike Krul who is a vampire. It is just so unfair I mean Ashera Tepes was a vampire himself but thanks to Sika Madu he is a demon totally seperating the two.

Sorry for the late response, was busy with other things.