At this rate, Family Day at school is gonna be real weird for Kunou - but I'm sure she'd still be happy for having such a big family.
"And who might this be, Lady Kunou?"
"My grandma!"
"How nice-"
"-she's daddy's wife!"
"-hah?"
Hmmmm.... nice Venelana as a waifu. Remember folks, she's a Devil and I doubt she has any shame in rewarding her savior even though she's married. Common sense don't exist as a much to non-humans anyway.