KEYAKI SHOUTENGAI SAKURA NO YU

Keyaki Shoutengai Sakura no Yu summary:

Tatsumi Azuma, a third-year student at Keyaki High School, accidentally bumps into and fractures Shunpei Eguchi’s hand. Shunpei Eguchi is a second-year student at the same high school, rumoured to "kill anyone who makes eye contact with him."
Out of fear of retaliation, Tatsumi pleads with Shunpei that he would do “anything”… Who knew that Tatsumi would end up helping out at Shunpei’s family-run Sakura Bathhouse?!
Brought to you by Tsubaki Yuzu, the heart-warming story of a fierce, intimidating junior and a sociable, bespectacled senior!