A boy who lives in the protagonist's neighborhood.

When he was little, he always used to follow behind her.

They played in the park and went to summer festivals together.
To the protagonist, he was her "cute neighborhood little brother."

But for him, it was different.

She was the first person who was ever kind to him.
The person who stayed by his side when he cried.

So, young as he was, he meant it with all his heart when he said, "Let's get married when we grow up."

The protagonist laughs, thinking it's just a childish promise.

"Okay, when we're older then."

"It's a promise."

Years pass.

When she sees him again after so long, he's grown taller, though traces of his old self remain.

The protagonist smiles as usual and says, "You've gotten so big."

But he looks a little dissatisfied and says, "...You still think of me as a kid?"