flowers have no tomorrow
As Chapter 130.5: -17 Prelude for the Straying Stars reveals, Hinamori Momo grew up in Rukongai, the outskits of Soul Society, alongside future Captain Hitsugaya Toushirou.
At some point, she enrolled in the Shinigami Academy. Excelling in Kidou, she became a member of an acclerated class where she befriended fellow future Vice Captains
Kira Izuru and Abarai Renji. In her school days, Hinamori was cheerful, loyal, and looked out for the well-being of her fellow classmates, qualities which carried over to her time as Vice Captain.
The talented young Shinigami-in-training first encountered the Captain of the Fifth one day during what looked like a routine exercise. Hinamori's class, led by a few older
students, had gathered in the mortal world to practice soul burial. However, some gigantic Hollows appeared, killing two of the upperclassmen and sending the group into a
panic. But rather than retreat as instructed, Momo turned back, letting her emotions override her judgment. Renji and Kira joined her, and were nearly killed by the Hollows
until two Shinigami showed up to save the day: Captain Aizen and his Vice Captain Gin. Gin and Aizen proceeded to defeat the Hollows, and from that day on, Hinamori
admired Aizen and aspired to become his Vice Captain.
"Hinamori could not live without me. I made her that way."
Of course, all of this was a perfectly calculated plan on Aizen's part to gain a Vice Captain that trusted him entirely. He became Hinamori's idol. The three young Shinigami
became members of the Fifth Division, and Hinamori later became Vice Captain, while Kira became Vice Captain of the Third under Gin. The hot-blooded Renji was deemed too
uncontrollable to be a part of Aizen's plan, and was eventually moved from the Fifth to the Eleventh, and then went on to become Vice Captain of the Sixth.
While serving as Aizen's Vice Captain, Hinamori longs for his approval and always trusts his advice. When Ichigo and co. invade Soul Society and everyone panics,
Momo looks to Aizen for guidance. His words seem to be the only thing that can calm her down. After his apparent death, she goes berserk. When Aizen's letter implicates
her trusted friend Hitsugaya, Hinamori cannot hold back from fulfilling Aizen's supposed final wish, even though she admits that she does not want to believe Hitsugaya is guilty.
As for Aizen, it's clear that Hinamori was simply a puppet. He looked for a quick way to discard her after she served her purpose, and when Histugaya and Kira failed to kill her
themselves, he calmly took up the deed. There was no emotional attachment of any sort on Aizen's part; Hinamori was simply a tool to be used, just like everyone else.
His influence went so deep that, after Hinamori recovers from her wounds, she begs Hitsugaya to "save" Aizen, still believing that Aizen must have good reasons for his actions.
She claims that someone must have forced him to do what he did. Hinamori eventually realizes that Aizen is the enemy, but the fact that it takes so long for her to do so, even
after nearly being killed by Aizen, is a testament to the hold he had over her.
Hinamori is someone I've always viewed as a tragic character. I really like her; she's kind, friendly, strong, and not even close to being as na´ve or weak as fandom tends to
portray her. Her main downfall is that she's overemotional, which is a strange thing to attack a character for in a series full of bloodthirsty lunatics. It may be easy to condemn
her for such blind loyalty, but if this site proves anything, it's that Aizen is one hell of a manipulative bastard, and Hinamori is just as he wanted her to be. Overall, I find her
story really quite sad.