Glasses Senpai

Glasses Senpai is an unnamed character in Ueno-San wa Bukiyou. She is a year older than Ueno.

Appearance
She has short, black hair and black eyes. She wears glasses very similar to Yamashita's.

She has been seen wearing a girl's uniform, a swimsuit, and the gym outfit.

Personality
She seems to be a gloomy person, telling Ueno that the Science Club will be disbanded if it's only her and Tanaka. She blames Tanaka for imagining her naked. She follows the Bunny-Ear Senpai around in Chapter 60.

She is similar to Yamashita in these respects.

History
The following events are in chronological order, rather than by chapter:

Chapter 60: She is with Bunny-Ear Senpai when she grabs Ueno to force her to join the Science Club.

Chapter 81: She is present at the relay race.

Chapter 70: She dresses in a swimsuit with Bunny-Ear Senpai to use Sprin-kun. She is a downer about the fate of the Science Club.

Ueno
She does not reassure Ueno about the future of the Science Club, but isn't hostile to her.

Tanaka
She seems hostile to him, accusing him of being a pervert. This combined with her dialogue at the end of Chapter 70 might hint that she doesn't have faith in him.

Bunny-Ear Senpai
She follows the Bunny-Ear Senpai around. She also tells her to not make up a story as to why the Science Club has to water the school grounds, and stops her from thinking of more evil ways to use Sprin-kun.

Trivia

 * A girl who looks like her appears in Chapter 4. Due to the panel being about not touching the girl, the girl wearing a swimsuit, and her apparent suspicion of Tanaka being perverted, this appearance could be in reference to her.