
If I understand correctly, unless there is a twist somewhere, they are siblings in the sense that the bodies are, but FL’s soul is someone who isakaied (traveled to an alternate universe). Who is to say if bro always loved his “sis”, or if he fell in love with her after the new soul entered the body

If I’m reading this manga right, it looks like he’s loved her since she was a child and intended to marry her before our FL possessed his sister’s body. FL didn’t possess his sister’s body until after she became a teenager, and by that time he was already obsessed with her. I was hoping it was one of those “we’re only siblings in name not by blood” stories but unfortunately this is not the case…
This is...weird. someone tell me theyre not blood related