false frames
man without identity

Sousuke Aizen is Bleach's original villain and Number One rascal. His presence is important to the world of HitsuHina, though not in the most pleasant way. For one, his intelligence is at an almost hateful level which only Urahara can rival at this point of the game. Boy, didn't he fool everyone so thoroughly at first with that "corpse" of his!
On the surface, what Aizen has done to Hitsugaya and Hinamori so far is simply horrifying. Not only was he able to scare two young and innocent hearts stiff with one plain "will", a single swift of his elegant sword was almost successful at erasing two important forces off Soul Society's elite military. And what's worse? I don't think either Hitsugaya or Hinamori had ever been able to "hate" Aizen completely (In fact, Hinamori is not over Aizen's illusion yet.): there's more sadness and confusion at Aizen's betrayal than fury in our story.
Nevertheless, we cannot be completely pessimistic. Contrary to common beliefs, certain aspects of Aizen's action towards HitsuHina might inflict positive influences on them in the long run. To be sure, Aizen was able to make Hitsugaya and Hinamori see how young and naive they were in the most effective way. "A friend of today might be an enemy of tomorrow" - the entire Aizen scenario was a powerful lesson of life to our boy and girl if nothing more. Nobody can tell what might happen next in a hierarchical world like Soul Society, anyway.
Aizen's evil plot is, by all means, a turning point in Hitsugaya and Hinamori's life. In Hitsugaya's eyes, Aizen was one of the few Gotei 13-Tai figures whom he had full respect for (alas, it's no easy task to impress our ice genius even if you're his senior); as for Hinamori, Aizen was that "absolute" existence (possibly a first crush as well) who made her shift left and right under all circumstances. Because both Hitsugaya and Hinamori's feelings for Aizen have reached a more personal than professional level compared to their other acquaintances, there should be a significant leap of progress in their own relationship - as friends, or maybe more - if they were ever to get over the shadow of Aizen's memories. The level of trust between the two would climb to a completely new ground, where many flowers of possibility might bloom.
Even if Hitsugaya and Hinamori were never able to let go of their past in regard to Aizen, they would still form a stronger bond than before as two sharing the same pain throughout their lives. I would prefer the opposite case, though: Hitsugaya simply doesn't seem like someone who'd cling to a past failure. The same can't be said for Hinamori, but then a shonen manga is never without some unsolved bitterness.
All in all, Aizen is undeniably the key person to Hitsugaya and Hinamori's relationship. Was he just a premonition of doom's day or a catalyst unnoticed by bare eyes? We shall wait until Mr. Kubo gives us a proper conclusion, if he ever manages to.











