In horse racing lore, two horses are only considered “siblings” if they share a dame, a mother.
This makes sense on a practical level because one stallion can breed with many mares in a short period of time but a mare can only have one pregnancy at a time, a pregnancy that lasts about 11 to 12 months while at it. Not only that, but a mare might have descendants from many different stallions and said descendants might not necessarily follow the same path, be as successful, or even be in a similar timeframe even if they are.
Scarlet Bouquet, Daiwa Scarlet‘s mother, started her breeding career in 1994, 10 years before Daiwa Scarlet was born, and Scarlet herself has a Brother with as many notorious accolades in Daiwa Major, but Daiwa Major was born in 2001, meaning he started his career when Scarlet was born.
Quick sidenote, but because Daiwa Major is descended from Sunday Silence, and Scarlet is descended from Agnes Tachyon who is descended from Sunday Silence, Daiwa Major and Daiwa Scarlet have basically 75% the same parentage in a roundabout way.
So anyways, despite Mayano Top Gun, Narita Brian, and Tanino Gimlet being all descended from Brian’s Time, they’re not really considered “siblings” either in-game or in the real world. In contrast to this, Narita Brian and Biwa Hayahide are, so far, the only characters with a shared mother (Pacificus), and as such the game treats them as siblings that grew up and lived together.
edit: Someone pointed out to me that Mejiro Ramone and Mejiro Ardan also share a mother now (Mejiro Hiryuu), but that actually goes into how the Mejiro girls are treated relationship-wise and other characters with similar names, so let’s leave that for later.
If you remember, I tried to figure out who Machan’s “little sister” might be by following the thread of Machan’s dame’s other descendants after Machan. It was because of this.
Also, because they were born one after the other, there were actually expectations on if Hayahide and Brian would compete together. They almost faced off in Arima Kinen, but Hayahide had to retire from an injury in the Autumn Tenno Sho right before it. Of course, the game actually plays with these ideas, but that’s a story for another day.
But the thing I actually wanna focus on with this prelude is the fact that, at least in anime-adjacent stuff, Hayahide and Brian are probably one of the very few cases of siblings that feel like siblings. Like someone with an actual sibling close in age wrote them.
Hayahide is the bigger sister. As the eldest sibling she had a lot of expectations put onto her, not to mention also taking care of Brian who she loves dearly. Hayahide comes accross as reliable and caring, like the kid that had to handle a lot growing up, but in a very natural way. Hayahide doesn’t come across as someone that’s trying to be like that, but as someone that just is, and because of this she can afford to be goofy more than once.
So when you train her or see Hayahide talk, you hear her talk about Brian as the baby sister that cried when Hayahide had to leave for a christmas party, the little girl that she had fights with because they had to share plushies, the little kid that refused to eat her veggies and was afraid of ghosts and by extension of any random shadows that popped up. She doesn’t remember this as a weapon agains Brian, rather, they’re just precious memories of her precious younger sibling.
Then you see Narita Brian.
The cool girl with the vagabond image, the quiet, stoic member of the student council, the prodigy on the track.
If you think she wouldn’t take kindly to Hayahide having all these shameful stories about her you’d be absolutely right. Especially because when you spend time with Brian it becomes clear that she is still that same capricious child, she just tries to hide it behind a rough exterior… but that rough exterior is worth jack and shit when she still refuses to eat her veggies and is very clearly avoiding anything that needs her to deal with other people not named Hishi Amazon.
You can get Twin Turbo to eat her veggies if you tell her eating everything on your plate is a game, just saying.
So how does Brian react to Hayahide getting too personal in public? She calls out the size of her head. Having a big head IS Hayahide’s one big complex, but the joke is that, in Brian’s arsenal, this is the ONLY thing she has. Adding yet another notch of a character that is clearly trying way too hard to be cool when in practice she’s that same little kid just stretched vertically.
Mind you, it’s clear that Brian appreciates Hayahide a lot and goes to her when push comes to shove, but you can also kinda get why she’s so reluctant to be the “little sister” more than necessary.
And there’s something just so… delightful about their relationship. Sibling relationships in anime-adjacent stuff tend to fall too hard in the extremes of “borderline fetish by people idealizing the concept”, “non-entities by people that probably didn’t think too much about their own siblings”, and “a bunch of faceless mouths to feed”. So to have a relationship where you have two characters that very clearly care about each other and are part of each others’ lives, but their perspective is skewed by their upbringing and even their personalities have been shaped in some way by growing up that way is really refreshing.
Even at her worst Hayahide comes off less as a siscon (sister-obsessed) character and more as just a girl befuddled by her loving little sister growing colder in her teenage years and adoring any glimpse of that girl still there.
It also adds a lot to Hayahide’s relationship with the rest of BNW where she just becomes the big sister of the trio without trying (down to being a busybody about them eating well), and also to Brian’s relationship with Mayano where she’s basically forced to deal with a little sister of her own.
