Idk, I definitely call both my brothers bro, but I'm also 10 yrs younger than one and 21 yrs older than the other. They're also both half-bros tho, so maybe that's it
I've also used brochacho here and there since learning it
my siblings and I call each other then most derogatory nicknames we for each other since we used to argue and fight a lot growing up unless shit is serious. then it's "hey (actual name)"
my home life wasn't super stable so I wonder how many families have this kind of sibling relationship
Luckily, though an only child, I had plenty of friends with siblings and I quickly caught on to that 'sis' or 'bro' was never used in anything except the most facetious fashion.
Oh I literally almost never use my sister's name. Like not when I'm talking to her and also even if I'm talking to other people I'll just say my sister. Sometimes I say my big sister which confuses people because I only have one.
Yeah the primarchs do it, and it's kinda weird. But they are inhuman monsters that have to serve as generals and politicians, so I forgive them.
When space Marines do it the it's kinda like how priests refer to each other as brother, but also battle brother is a rank.
I think it is also there to make things seem more theatric/dramatic. Like just how many books start with a dramatis personae? We're not reading about people, we're reading about characters in a space opera. No matter how you look at it, it's still pretty silly.
Me and my sister call each other “trash” (sounds better in our language). We constantly make jokes about the other being trash (I.e “I gotta take the trash out” with a subsequent “why do you need to go out?”) etc.
My brother and I greet each other by straight-up shouting each other's names. Sometimes we go back and forth in increasingly-angry tones, before finally ending with a sweet and gentle, "... hi."
My bro used to call me shitpants (in German) and I callt my cousin lovingly "little shitpants"
Also been called clevershit a lot by my siblings (which was fair ig.) But when things got tough they had my back.
All my siblings are way older than me(only lived with one for 4 years), and every one of them besides my sister has greeted me as little shit at some point.
i have a lot of siblings, and the only time ive ever called any of them "sis" or "bro" is when my older step brother and i make fun of the "step bro" memes
Since we're taking a poll in these comments, my go tos for my brother are "Hey Brotato" and "Hey Broseph", while my sister gets called her shortened first name (which she doesn't even go by, and hates, haha). Only time she gets sis is if I'm feeling silly and yell "Oi Sis!!!" with a vague cockney or pirate accent for some reason.
I have two sisters and I've called them "sis (insert sister name)" since so young that when I was about 4 someone asked my sister's name and I said "sis Karol" as if sis was part of her name lol. Only one note, I said "mana" instead of sis, I translated it to sis here because it is pretty much the same meaning in all ways