#/George left everything so vague around Robb's will/ and Cat and Robb literally spell everything out in the conversation they have

[fromtheseventhhell]

“So you pray. Have you considered your sisters? What of their rights? I agree that the North must not be permitted to pass to the Imp, but what of Arya? By law, she comes after Sansa…your own sister, trueborn…” “…and dead. No one has seen or heard of Arya since they cut Father’s head off. Why do you lie to yourself? Arya’s gone, the same as Bran and Rickon, and they’ll kill Sansa too once the dwarf gets a child from her. Jon is the only brother that remains to me. Should I die without issue, I want him to succeed me as King in the North. I had hoped you would support my choice.” (Catelyn V, ASOS)

This is truly one of, if not the, most erased passages in the books. People either completely ignore its existence or act as though George wrote it in some secret, coded language that makes it all ambiguous.