Masashi Arai (荒井将史, Arai Masashi) is a 2nd-year student at Seishun Academy. He is a member of the Seigaku tennis club and is usually seen with Ikeda and Hayashi, also 2nd-years. Arai tries to get back at Ryoma by stealing his tennis bag and challenging him to a match, offering an old wooden racket as a replacement. Despite this, Ryoma effortlessly mauls Arai until the match is stopped by captain Tezuka Kunimitsu.