Hisagomaru
Hanatarou Yamada is a gentle soul, which made the form his zanpaktou took upon release unsurprising to those of his instructors versed in the deeper mysteries of sword-lore. Had they waited long enough to see his sword's secondary ability before waving him on to 4th Division, they would have been puzzled. A bipolar zanpaktou is a rarity, and might have warranted a stint in the 11th, to see if there was some hidden part of his psyche that this destructive ability reflected.
Hanatarou is rather glad he didn't have to go through that.
His zanpaktou spirit, however, a busty woman with blonde pigtails and a diamond-marked forehead, who is intoxicated and violent far too often for the nervous shinigami's liking, is not. She recognises that the 11th Division has rather more fun, and is certain (though she couldn't say how) that she's done enough hospital work to last a literal lifetime.
Despite this split in their tastes, Tsunade is obscurely fond of the attentive, caring young man who became her wielder. He reminds her of a distant memory, a fellow healer whose face was lost in her reforging. Like the Captain of the 4th, she looks upon Hanatarou as a mother does her bumbling-but-good-hearted son. She's sure he takes after her. After all, she'd been a ruler in her life, hadn't she? His election to Captain-Commander Yamada almost a century after the Winter War was only to be expected.