Where did you find the spoilers from?
To be honest I don't believe that.. I mean if it is through adoption then sure but biologically I don't think that is the case. We know that karma’s biological father in north Korea was the one who started doing experiments on her.. And I highly doubt that if she was her adopted-father’s biological daughter stuck in north Korea then judging the way he is. He would have done everything to get her out and took revenge for experimenting on her.. I mean they are technically adopted siblings? Since she is adopted but real siblings? I don't think so.. We also saw a chapter where the adopted father pointed a gun at her head for not following his plans.. So again I don't think they are biological siblings. They are not related siblings.
Not by blood. One is adopted.
Hyena and Karma are siblings?? I didn't even consider that... ohmy