Yokochini, known as Weasel in the English-dubbed anime, attends a different high school in Karakura Town than Ichigo Kurosaki. He is the leader of a local gang of troublemakers.
Yokochini fits the stereotype of a juvenile gang leader. He usually avoids direct violence, letting his followers handle the dirty work. He relies on their obedience and fear to maintain control, although he can't stop them from calling him Yokochini, a name he dislikes. When his victims fail to show fear in his presence—or, as in Chad's case, refuse to fight back—Yokochini often becomes unsettled.
He can be quite cunning when he puts his mind to it. For instance, he has his goons attack Chad and then run away when Ichigo arrives, leaving an open line to spy on their conversation and discover the best way to hurt Chad. However, when violence comes his way, Yokochini crumbles just as quickly as anyone else.
(Source: Bleach Wiki)
