well fuck, to be honest i prefer these kinda of stories where they actually end up falling for the person who took care of them instead of abandoning them the minute the person they were with before shows up :/
From the announcement in the first page, all of this happened in a single day. And based on Haruna's line, she knows how it feel to be a little sister missing her older sister. At the end the reason she cried perhaps because she was reminded of the time being the last one standing, all her sisters already sunk. A relief for Yamashiro to have Fusou back and her own situation that she has all her sisters again. I don't think this is truly a bad case. The Kongou class & the Fusou class will have good relationship later on.