(Tutor + Net King) There Is No Tennis in the Parallel World

The protagonist of the parallel world, Juzaburo Mori, is the ancestor of Vongola's first generation Arashi guardian G. His cousin is Hayato Gokudera, and his parents are members of the Vongola Foreign Counseling Department. He was attacked and both his parents died. He escaped because he participated in a tennis match. After that, he joined the Vongola Foreign Counseling Department and did not have any interactions with Rikkai Dai and others until ten years in the future - Idea: You can still fall in love at first sight even if you have no contact with tennis.