Shimoyanagi

Shimoyanagi is a friend of Sasayan from baseball team. He likes Asako Natsume, but he has trouble talking to her. Initially, Sasayan tried to get him and Natsume together, but Natsume left because she couldn't stand the boy's laughter. Later, Sasayan discovers that Natsume fell in love with Mitsuyoshi and so Sasayan apologizes to Shimoyanagi. He has a rat named Gurigura. He is very friendly and kind to people.

(Source: tonari-no-kaibutsukun.wikia.com)