Yanda

Proper Japanese Name: Yanda (ヤンダ), real surname Yasuda (安田)

Yotsuba Koiwai's fair-haired Nemesis

Yanda is a friend of Yotsuba's father Koiwai, and the only character in the series who Yotsuba bears an ongoing grudge. This stems from a disastrous first meeting where Yanda and Yotsuba found themselves in a spat after Yanda attempted to gain admittance into Yotsuba's home in her father's absence. Yotsuba took Yanda's playful, childish teasing deathly serious and a great enmity was born.

Yanda has shown willing to reconcile with Yotsuba, but she's not interested. He still teases her from time to time, but never as severely as on that first occasion. Yanda in turn, is often the target of teasing and minor insults from Jumbo and Koiwai, though he can take this sort of treatment a lot better than Yotsuba can.

Alike Jumbo he's also shown an attraction to Asagi, but apparently has a girlfriend of his own, though she hasn't contacted him in a while and might have dumped him.