I know everyone has their own interpretations of 천사 but in terms of Supernatural, are all 천사 actually related 또는 do they call each other brothers and sisters for another reason? I'm sorry if this 질문 is stupid.

It's definitely not a stupid 질문 !

They aren't literally siblings, because they weren't literally born, they were created. They all have the same creator, who is to them their father, since 천사 do not physically breed. Although this doesn't mean he's not "really" their father, because this sort of father-child/creator-created relationship is much 더 많이 powerful and real to 천사 probably than how some humans consider God to be their "father." 천사 exist in a spiritual way, and a spiritual connection is probably 더 많이 important than a genetic one. I don't think the 천사 even have any genetic material, until they possess a human vessel, they exist on a spiritual plane. In this sort of situation the concept of what is a parent 또는 sibling becomes much 더 많이 abstract, and whether 천사 are actually siblings depends on how literal your definition of the word is. However I think the 천사 consider eachother to be their brothers and sisters.

That's my take on it.

I think its like a respect thing.

What that means is as christians & followers of christ we are all related for God is are creater he is are father in heaven so that makes all of us brothers & sisters in Christ. Talk about your Big families!
Hope that didnt confuse 당신 to much,

They're actually related -- although there are so many of them that I doubt they've all met each other .. they ARE all brother & sister. :)