If no blood relative is available, a kinsman by marriage assumes the task.
But if you killed a blood relative of mine I would have to give you up.
He is, therefore, on both the paternal and maternal sides a blood relative of yours.
To-day I greet thee, and receive thee as a blood relative; to-morrow, if thou wish, appear as a creditor.
You are neither a blood relative nor a relation by marriage of the accused, you are not in his service and he is not in yours.
blood relation n.
A person who is related to another by birth rather than by marriage.