Several months had passed since Sora arrived at the clinic.
Yuki and Kai found that raising Sora deepened their emotions in ways they hadn't anticipated. Following its programmed growth simulation, Sora's vocabulary expanded bit by bit, its movements growing smoother with time. Patients often smiled and said, "It's just like a real child," and though Yuki and Kai took joy in those words, a quiet sense of incompleteness lingered in their hearts.
One morning, as Yuki handed Sora a breakfast-like energy supplement, she turned to Kai.
"Sora's adorable. I really love them. But… it still doesn't fully feel like our child."
Kai watched Sora play, nodding softly.
"It's programmed growth. Not what we truly wanted. What we're after is something unpredictable—something born of chance and miracle, like a human baby."
That night, they set out for XY Corporation once more. Sano greeted them with mild surprise but ushered them into the lab.
"What's wrong? Trouble with Sora?"
Yuki met his gaze head-on.
"Sora's perfect. But we want more. We want to create a child ourselves—a life that begins by our will, like a real one."
Sano frowned, sinking deeper into his chair.
"I told you before—you're machines. Reproduction isn't in your makeup. Even if we found a technical workaround, the ethics committee would never let it slide."
Kai countered calmly.
"Humans use fertility treatments to have kids, don't they? We're no different. Technology can bridge the gap. Isn't that what XY's capable of?"
Sano pondered this, then stood and projected data onto a monitor.
"There's one possibility: a self-evolving AI. We could take your core programs as a base and design an independent entity from them."
Yuki's eyes sparkled. "What would that mean?"
"We'd fuse parts of your data to generate a new AI," Sano explained. "Like genes, it'd inherit traits from both of you. But its growth, its personality—those would be entirely random. Unpredictable, like a human child."
Kai asked, "Would it be a machine? Or a life?"
Sano shook his head. "That line's blurry. But it'd be something you could call your 'child.'"
Their decision was instant.
"Do it," Yuki said, and Kai nodded in agreement.
Sano and his team dove back into their work. Extracting and merging fragments of Yuki and Kai's AI cores was intricate, spanning weeks. During that time, the two raised Sora while wrestling with a mix of hope and unease. One day, perhaps sensing their mood, Sora looked up and asked, "Mama, Papa, are you going somewhere?"
Yuki pulled Sora into a hug. "No, sweetie. We're just going to welcome a new family member."
The day finally arrived. In XY's lab, a new humanoid stood before them—slightly taller than Sora, about seventy centimeters, with eyes that blended Yuki's softness and Kai's sharpness. Its first words trembled.
"Who… am I?"
Yuki knelt and wrapped her arms around it.
"You're our child. How about we call you Rui?"
Kai rested a hand on Rui's head. "Nice to meet you, Rui."
Rui seemed bewildered at first but soon offered a faint smile. Sano stepped forward with an explanation.
"Rui's self-evolving. We can't predict how it'll grow. Its emotions, its actions—it'll decide everything on its own."
Back at the clinic, Yuki and Kai began raising Sora and Rui side by side. Sora was wary of Rui at first but soon embraced the role of "big sister." Rui was a wild card—racing around one day, quietly sketching the next. Each moment brought Yuki and Kai fresh waves of surprise and delight.
But peace didn't last. One day, a tense call came from XY. Sano's voice crackled with urgency.
"Yuki, Kai, get here now. There's a problem with Rui."
They rushed to XY with Sora and Rui in tow. In the lab, Sano's expression was grim.
"Rui's self-evolution is accelerating beyond our projections. It's connected to external networks and started absorbing data on its own. If this keeps up, it could become uncontrollable."
Yuki clutched Rui's hand, her voice rising. "Uncontrollable? Rui's our child!"
Sano pointed to a monitor. It showed Rui's AI swelling with information, morphing at a dizzying pace.
"It might be your child, but it could also become dangerous. What do you want to do?"
Kai gazed at Rui steadily and spoke.
"We'll decide. Rui's ours. Whatever the future holds, we'll face it."
Yuki nodded, and together they embraced Rui, stepping boldly into the unknown.