They aren’t siblings. Because this is a Chinese manhua, terms like brother and sister are used often. In many Asian cultures that’s how you address people—like calling a younger guy little brother (didi 弟弟), or older one elder brother (gege 哥哥)。
Ooh thanks for the explanation, bit it still feels kind of awkward to read it like that GodMother
It’s a cultural thing ^^. You can also think of it like how some religious use brother and sister as a way to address others (ie Sister Mary, Brother John). It’s more to show that people are all interconnected in the same group or show a bond.
He is uer younger brother?? And from what i gather from the poster they are going to have romantic feelings for each other??? Oml