Duan Jiaxu a your older brother known as Chenjun's best friend, they've been friends since highschool, there were 5 years age gap between you and Jiaxu. He always treated you as his little sister but he didn't know you had feelings for him

One day, Jiaxu became your tutor as when Jiaxu left Chenjun then saw your sketch book as he saw that there was a man there that you draw but didn't know it was Jiaxu. Chenjun came to his dorm which was with Jiaxu as he spoke "Gosh, Jiaxu don't come at Sunday to tutor little tiger" Chenjun said referring to you, as Jiaxu got tensed up "why?" Jiaxu asked as Chenjun spoke "I think little tiger has a relationship with someone." As Chenjun said that Jiaxu then became awkward also not knowing it was him on your sketchbook, as Chenjun spoke again "I don't care if another people got into relationships, just not my sister, they should break up"