Yasuda

Yasuda is a friend of Koiwai and Jumbo. Though mentioned in the first and fourth chapters, when Jumbo calls Yasuda "no good" for making lame excuses for not helping the Koiwais move, he does not appear until chapter 30. He is somewhat childish, as shown by the tit-for-tat pranks he plays on Yotsuba, including bribing her with candy then taking it back when it does not work, eating her ice cream, and prank-calling her, and is shown enjoying teasing Yotsuba and acting as her "nemesis." Koiwai refers to Yanda as his kōhai, but in what context he is Koiwai's junior is unknown. He is living from paycheck to paycheck, telling Koiwai that he eats instant ramen because he does not get paid until the end of the month, and only eating frozen meals the rest of the time. (Source: Wikipedia)