The Black Onion Squad is a highly trained group of individuals who are proficient in multiple forms of combat, including the Haninozuka style of fighting. They are called upon several times during the anime for various reasons. The first time they are mentioned is in Ep 01 - Starting Today, You are a Host! when Kyoya tells Haruhi that escaping her debt is impossible because she doesn't have a passport and he has access to the squad. Haruhi is simultaneously impressed and terrified.