oh... i never know sayaka and madoka's birthday is on the same day.... so it's why that you make madoka as sayaka's grandchild?
yo-
ryo here, the other author of this fic, well yurin is the main writer, i mainly edit her drafts and give ideas
anyways, about your question it's just a coincidence honestly... i just learned that they have the same birthday recently when yurin said that (when she was writing #14 of this fic) haha xD
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when we are starting this fic, we first thought of the family settings of sakura, natsu, madoka, chihiro and aoi and ended up like the one in the intro
for madoka, when we thought of what family setting she have in the story, we just thought of jurina coz she was jurina's oshimen in hakata hyakkaten,
and coincidentally she's somewhat like rena plus cool and mature beauty like jurina
so she'll be jurina's daughter and for jurina's family setting, all i can think about is SaeYaka
i mean coolness, beauty, ikemen, mature looks, angst, talent and the hyperness of the two she got all of that
(sorry if i was rather exaggerated
)
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but thinking about it,
madoka is:
cool
beautiful
mature
smart
talented
tall
and she have somewhat queen type of personality (rather than ojou-sama i say she's more like a queen [like she is somewhat demanding] )
plus she isn't afraid to make silly faces (in real life matsuoka natsumi said she was funny, and she likes that part of her
)
...so thinking about it, sayaka too is cool, beautiful, mature, smart, talented, funny,
and sayaka have a queen attitude xD (as masuda yuka and miyazawa sae said in an interview in their subunit [DiVA] before their disband)
and also they both hate to lose