Futurefic, AU continuation from the 260s chapters of the manga;
Resulting spoilers therein. Speculation on Ichigo's lineage.
The Nuclear Family
So great was his shame that Shiba Kaien, once the Vice-Captain of the Thirteenth Division and then Novena Espada of the Arrancar, foresook the seat of responsibility that had never been filled with a successor, and upon his return to Soul Society he went--was brought to--to occupy the one position he had never abandoned, that of favored eldest brother and best beloved of the clan Shiba.
It was there that he remained in the care of his sister, loud as he remembered her, and their much-grown brother. Adjustments were made to account for his new condition, and there were the required kickings from Kuukaku for ending up in such a state at all, but there were few who could hold a grudge over a loved one returned from the dead. Kuukaku was not among them, and Kaien was accepted as a brother returned exactly where he belonged; however, this did not lessen the shame in his heart for the actions he'd performed, possessed of a malevolent Hollow or not. For the most part, aside from those few individuals with the political or emotional power to force an audience, Kaien kept to his retreat, for once playing the coward, unable to face those he'd hurt.
Decades passed in this manner.
Eventually, one person tired of this behavior. His killer, his savior, his protege; if Kuchiki Rukia could forgive herself, she reasoned, why could not Shiba Kaien? Was he admitting the superiority of the House Kuchiki? Never, he swore. And so there came a private meeting between the two. Many words passed between them, and much awkwardness permeated the visited, but by the time she'd gone, both felt that things could just possibly be normal again between them, and Rukia soon became an expected visitor to Kaien's home.
In time, she brought her husband and child.
"Ichigo, hold the baby up so Kaien-dono can see him," she ordered. He did so. The baby gurgled. So did Kaien.
"He looks just like you, Kuchiki," he cooed. "Gootchy gootchy goo!"
Rukia beamed, then jabbed Ichigo in the side as he began to lower the infant. "Let him get a good look," she scolded. "It isn't as if we get to visit all the time."
"My arms are tired!"
"So speaks the great hero who ended a war and saved Seireitei with his might," she said. "Kaien-dono, is that a new tank?"
"Yeah, thanks for noticing!" The floating skull bounced excitedly in the row of connected aquariums that lined the walls and extended throughout the rest of the house. "A birthday present from Kuukaku. She found a new glassmaker in West Third. Really helpful, considering what happened the last time Sentaro and Kiyone came to visit."
"They send their apologies," she said. "They only meant to show their exuberance, not shatter your your dwelling."
"Ah, it's all good, I know how they are." Kaien grinned--or, more accurately, continued to grin for lack of choice regarding facial expressions. It suited his mood, though. "How about you? Keeping everything going like I would, Vice-Captain?"
She smiled. "I could not hope to live up to your example, Kaien-dono."
Kaien snorted, and a stream of bubbles floated to the top of the water. "Yeah yeah, so you say. Sooner or later I'll get you to admit you're doing a great job."
"I had a very good teacher, Kaien-dono." She bowed low.
"And you, Ichigo? How's everything going in the Fifth, little cousin?"
"Same as ever." Ichigo sounded casual, a tone cultivated by much practice in facing what he termed 'fucking weird shit,' and family visits with a Hollowfied skull removed from a smashed glass tube in Hueco Mundo and carried home under Rukia's arm would always count as that, no matter how many times his wife's fists attempted to correct his perception of the situation. "We're still finding Aizen's caches even now. He had some really messed up experiments."
"Uh," Ichigo started again. "Not that I think you--that's not what I--oh shit Rukia I think the baby's wet I'm going to go change him and get him a snack you two enjoy your visit bye."
"He doesn't mean anything by it," Rukia remarked as Ichigo fled. "He's just not used to how you look."
"Neither am I." Kaien sounded a little wistful. "But we all do the best we can, don't we, Kuchiki?"
"It doesn't bother me, Kaien-dono," she said loyally. She placed a hand against the glass and he floated to bump against it. "You are still you."
"I try to be."
"My brother sends his regards."
"Tell him to send his ass over here sometime. I can still beat him at shogi if he moves the pieces for me."
"I will tell him."
There came another silence, but not a painful one. It was the silence of old friends reunited, both grown older, wiser and stronger for the trials they've faced, together and apart. It was the silence of those who understand one another and feel no need to spoil things with words.
"Hey, do you want to see Kuukaku's new fireworks?" Kaien asked when the moment had passed. "She finished a doozy of a set last week, and it's about time that kid of yours got to see a show. He's got Shiba blood in him; it's his birthright."
"That would be lovely," she said. "Shall I fetch your traveling jar?"
"Yeah. You know where it is."
And so as night fell, the fireworks of the Shiba once again cracked and sparkled in the sky, family and friends stood together in communion, the colored lights above reflecting against the jar in Rukia's arms. And if things weren't as they once were, and never could be again, they were still content, and this was enough.