Pashirare Incha ga Jitsu wa Saikyou Datta Ken

The class rep, Shizuka, was worried about her classmate Usui-kun, who was always being bullied by a trio of delinquents known as the Three Idiots. One day, Shizuka gets caught up with some delinquents in town. The Three Idiots happen to be passing by and come to her aid, but are beaten back and it looks like they are in big trouble! Just then, Usui-kun, who had gone to buy drinks for them, leisurely returns—

"Oh, your friends are still here? Don't complain if I accidentally break them!"
Thump!!!
"...You too."
"Ouch, ouch, ouch!"

Usui-kun, whom she thought was being bullied because he was quiet, instantly destroys a gang of delinquents stronger than the Three Idiots!?

(Source: MF Bunko J, translated)

Note: Includes a mini-manga drawn by Rokui Shirabe.