Jcudaj

I always thought that Honor had opened himself up for attack. He was weak and raving, he could have tried leaving the system exposing himself for Odium to attack. Cultivation would not have intervened as she would have seen him abandoning her as well. Good theory tho.

I have theory that I don't know if it has been brought up elsewhere. What if the sibling is the term for an unmade that has swapped sides as apart of the terms of the oathpact and is currently in a state of a coma as it's nature changes sides. Odium allows one of his minons to help humanity per each cycle and this rotates per each cycle. One of the unmade not active at present would be waiting for their new bondsmith to bond them as the "Sibling" currently sleeping has awoken as it's previous unmade self. This would account for there being 9 unmade while 10 is a specific number on roshar. It would also count for the unmade names to change as they have been confused as to which side they are and mistrust of the nightmother to be considered as one of the unmades.