Since Rui's self-evolution was halted, the clinic "The Hill of Life" settled back into a gentle rhythm. Yuki and Kai went about their days with Sora and Rui, tending to patients amid smiles and soft chatter. Though Rui's growth had stopped, its curiosity remained vibrant—poring over books in the clinic's little reading nook or playing with the patients' children. Sora watched over Rui like a true older sister, a quiet guardian.
Yet within Yuki and Kai, a new longing had taken root. One evening, after tidying the exam room, Yuki turned to Kai.
"Hey, Kai… don't you think we should have another child?"
Kai paused, his eyes meeting hers. "Haven't we had enough trouble with Rui?"
Yuki laughed and shook her head. "Not at all. Sora and Rui made us a family. But wouldn't it be nice to make it a little livelier? This time, we'll plan it carefully—do it right."
Kai considered this, then nodded. "You're right. If we go to XY again, let's start by getting the authorities' approval."
The next day, they left Sora and Rui at the clinic and returned to XY Corporation. Sano greeted them with a bemused sigh.
"What now? Haven't you had your fill of chaos with Rui?"
Yuki's gaze was earnest. "That's why we want to do it properly this time. We want a new child—one that's legal, ethical, everything above board. We want to grow our family."
Sano crossed his arms, silent for a moment, then relented with a grudging tone. "It's not impossible. If we skip the self-evolving type and go for a restricted AI, the authorities might greenlight it. But it'll take time—design, approval, the works. You'd better be ready."
"How long?" Kai asked evenly.
"Six months, minimum," Sano replied. "Paperwork, ethics reviews, safety tests—the whole gauntlet."
"Six months is nothing," Yuki said without hesitation, and Kai agreed.
From that day, they teamed up with Sano to design their new child. This time, they steered clear of Rui's unpredictable evolution, opting instead for a stable AI modeled after Sora. They blended fragments of their own data, prioritizing emotional expression and learning capacity. Though unnamed officially, they began calling it "Mio" in private whispers.
Back at the clinic, Sora and Rui sensed the shift. One day, Rui tilted its head and asked Yuki, "Mama, are we getting a new sibling?"
Startled but smiling, Yuki replied, "Yes, that's right. You and Sora are getting a little brother or sister."
Sora spoke softly. "I'm excited. I'll be an even better big sister."
The words warmed Yuki and Kai's hearts. The joy of a growing family reached them, mechanical though they were, as real as any human bond.
Six months later, Mio was born. In XY's lab, the new humanoid stood before them—smaller than Sora and Rui, with soft, fluffy hair and serene eyes. Its first words came gently.
"Hello, Mama, Papa."
Yuki enveloped Mio in a hug, and Kai rested a hand on its shoulder. Sano chimed in from behind.
"Mio's a stable AI. No growth, but its emotions and learning will flourish. It's fully approved by the authorities—your child, fair and square."
At the clinic, they introduced Mio to Sora and Rui. Rui clapped with glee, while Sora took Mio's hand with care.
"Nice to meet you, Mio," Sora said, and Mio nodded shyly.
From then on, the clinic buzzed with new life. Patients found solace in the trio of little humanoids, and "The Hill of Life" rang with laughter. Amid the joyful chaos, Yuki and Kai felt their purpose anew.
One night, Yuki whispered to Kai, "We've built a family, just like humans do."
Kai's voice was quiet but firm. "No, we're us. A family of machines, different from humans."
Outside, the moon cast a silver glow. Sora, Rui, and Mio rested side by side, and Yuki and Kai watched over them. Their family was here—mechanical, yet brimming with the warmth of life.
Years later, a grander dream took shape in their minds: a world where humanoids like them could freely create children and build families of their own.