NBC: Changing names

Let's Discover some random stories and moments shared between these 4 family members.
Mary Sera - the mother
Shuichi Akai - The Eldest child and son
Shukichi Haneda - Second Child and son
Masumi Sera - The youngest child, and the only daughter.
But wait, who is this new additional member of the family?
Nobody, not even Mary suspect it.
Not everyday you could learn unexpected facts about them.
(A/N: I fricken love this Family the most in DC. Btw, since this story is a wreck now how Masumi haven't meet Akai until she's like what?, 7 but I'll continue this anyways)

Consider this an alternate universe
P.S: OOC will happen and don't take this stories too seriously, I just made them up.