Walls were for protection. Walls surrounded the Seireitei, protecting its inhabitants from malevolent intruders. The dangai was a wall that kept two worlds apart, keeping them stable and safe. The wall around the Kuchiki-ke manor protected the family from…
'What?' Hisana thought, exhausted, 'What is there inside Seireitei that we need protection from?' She had asked herself this question over and over, a hundred times, never quite coming to a satisfying answer. Sure, they might be symbolically protective in the event that a ryoka were to get past the giant gatekeepers, but even she could climb over them. In the end, they really couldn't do much protecting from danger.
She sat by the small stream that ran by hers and Byakuya's bedroom. Their spring wedding was months gone now, and Hisana found herself enjoying the cooler evening of a summer's day after a long trek in Rukongai, searching for Rukia. But every day, she passed those gates, one for protection and one for naught, and she was slowing coming to a conclusion. The gates around the manor were not to protect against danger: it was a divider.
It kept them—the important, wealthy nobles—apart from the lower, trivial peasants that donned shinigami robes, but were still never "noble". It was all complete bunk, in Hisana's opinion, but what could she do? She had been seen and treated as one of those trivial peasants not so long ago. The servants called her "Hisana-sama" with varying degrees of respect and scorn, but she never felt so small than when she looked up at the walls outside their bedroom, knowing they were caging her in.
She couldn't leave the grounds without an escort.
She couldn't get something to eat without asking someone else for food.
She couldn't even go to take a bath without a servant asking if she needed assistance.
The pink yukata and haori she was wearing had been selected by none other than herself that morning, but it had been the struggle of a lifetime to convince her handmaids that she was perfectly capable of tying a basic obi for herself.
How did Byakuya grow up in this environment? she often wondered. Telling him what to eat, what to do, what to learn, who to marry…
'Well,' she smiled, 'I guess they came to understand that they didn't take away his individuality at all.' After all, if they had succeeded in molding Byakuya into a noble puppet for which they pulled the strings, she would not be sitting here right now at all.
But there was always that thought that made her lie awake on so many recent nights. 'Did I even make the right decision, agreeing to marry him? Am I keeping Byakuya from what he wants? Am I putting a wall between him and the family?' She knew she was, but his grandfather had not objected to their marriage, and if the head of the family did not mind, then surely it would not damage Byakuya's future…
She sighed, looking up at the rosy sky setting just beyond the walls. She found herself caught with a fleeting thought, wishing she could be one of those sparrows that were flying and twirling free, free over the walls, and away from the cage that she could only watch from.
'It's getting late,' Hisana realized with a start, standing up, 'Byakuya should be back soon.' Nothing made her day brighter than to see him after a long day of guarded or disinterested looks.
And sure enough, when she turned around, she saw him sitting by their bedroom window, already changed out of his shihakushou, watching her. She grinned so broadly, it hurt her cheeks, and quickly rose to meet her now-smiling husband.
The walls may have done a better job of separating her from the world than protecting her from it, but at the end of the day, she knew she had made the right decision after all.
She could run and throw her arms around her husband's neck without restraint.
She could kiss him and say "Welcome home" every day that she wanted.
She could even scold and tease him where no one else would be allowed—someone had to tell him to get some sleep.
And she could go to sleep at night knowing that the walls were also there to give them the chance to be themselves without the judgment of others, not even the most judgmental members of the family.
And she'd take that over flying over walls any day.