Well, you know....
Childhood tiny boy get bullied or such, saved by Tabata, grow up handsome n strong...
Childhood tiny boy who look like a girl been dissed by classmate, but got complimented by Tabata, grow up handsome and want Tabata to think of him as cool instead of cute...
Childhood boy who is easygoing and justice of the day, taking up himself to be the protector of the timid mini-Tabata, grow up to be those sporty blunt guy and still think that he is the big bro of Tabata...
Etc, etc, etc, you name it... your choice...
(● ̄(エ) ̄●)
Or.... if you want normie route...
a transfer student who is as timid and as gloomy and as negative as Tabata came...
They have the same wavelength... he is like the boy version of Tabata...
No one want to show him around school, so the job got thrown to Tabata....
Later, he also help Tabata with taking care of the garden or something...
They click on quick and become the best friend, but because they are too lookalike, love was impossible to form...
However, the shitty kids in class start setting the two ups and teasing them as couple made in heaven or hell you name it...
As timid as the both are, they couldn’t speak up to defend themselves..
this shit happens for couple days, and Ueno as dense as he is, think all this was true and start getting jealous or whatever those feelings are....

With ueno dense like that, how will this couple get together?