Work Text:
Naki didn’t age, because they were a humagear. They needed regular maintenance and upgrades, but they still looked the same regardless of how much time went on. Any changes they made would be simply cosmetic, and Naki was content with their appearance.
As Naki remained the same in appearance, they thought about how humans worked in terms of aging. And how humagears worked.
Naki was an adult. But they had physically existed for many decades, while their appearance and apparent maturity was always of a young adult.
Naki had never been a child. There wasn’t really a child-aged humagear. Naki had never heard of one, and if there ever was one, they would have to be specifically designed to be a child.
Fuwa was a human. He was an adult who naturally aged. As he got older, his face changed and he got slower, even if he wouldn’t admit it. He was still fairly in shape, but his strength wasn’t the same now as he had been as a young Kamen Rider. Even if he would never admit it.
Naki did their best to not to point out Fuwa’s age, but always noticed it. Naki spent more time with Fuwa, and though he didn’t let them move in, he let them spend time with him.
Neither of them said it, but they both knew that someday, Fuwa would be gone.
And Naki would still be here, eternally a young adult.