I'm not sure if it's the source being weird or the wording of the TL but I'm not exactly clear on the family tree stuff going on here. Her grandfather's "10th position" secretary is the son of that grandfather's brother, and is in some inheritance/succession conflict where they try to kill each other?
Edit: and one of the Hashizakis was killed but not the other? Do we know which one? It probably doesn't matter which it was, though?