The Sasaki family is as elite as it gets, and one of its members, Tetsunosuke, has joined the Shinsengumi.  He would have joined the Mimawarigumi, a police force with pedigree, but he is considered a troublemaker, which is why he was sent to the Shinsengumi.  Kondo assigns Tetsu to Hijikata as an assistant, so Hijikata is forced to endure the new recruit...
It's for nasty kids that prick 
you if you get too close.
Así llaman a los mocosos que
 te hacen daño cuando te les acercas.
É para crianças más que pregam 
peças se você se aproximar.