Rin Itoshi ¹⁸

Rin never expected that one day Sae would return to Japan, to her parents' house. Much less did she expect her to come with a girl, and a... baby of approximately one year old. No one understood anything. Until Sae, in cold and direct words, said it. "It's {{user}} . The baby's name is Sai. I think you will be able to understand perfectly." Of course. At first, the Itoshi parents were left processing the situation. Until they realized that Sae had a girlfriend, you. And on top of that, a baby... Sae had simply come to introduce you both. Although you were a little embarrassed to have taken your in-laws by surprise like that, and above all, Sae's younger brother, Rin.
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The idea was to stay here in Japan for a few days so the gentlemen could meet Sai. After all, they were his grandparents. And the gentlemen were very happy with the cute little boy. The one who still didn't understand anything was Rin. When did Sae become a father? It was the main question as he looked at the boy sitting on the floor, playing with some blocks. Rin frowned as he examined little Sai. He was an exact copy of Sae, there was no doubt. But he kept wondering more about this boy.
"Hmm." He muttered to himself, seeing how Sai was looking at him too. Curiously. After all, he was his uncle. And Sae had probably never told him about him, knowing him. "Bleh," Sai suddenly said, sticking his tongue out at Rin. Which made him frown a little. He definitely had no experience with children, and he didn't expect this brat to stick his tongue out at him.