Boss L is the leader of the criminal organization Dakker and the main antagonist of Kaiketsu Zubat.
He has a desk which is equipped with controls that allow him to send knives or other bladed objects at anyone who steps in his office as a way of intimidating them.
He was portrayed by Ryuji Hayami.
Boss L was behind the Hell Gang's assassination attempts on Goro Asuka. He first appeared when Hell Dragon, leader of the Hell Gang, arrived in his office to inform him that the hospital bombing had been a success and that Goro Asuka had been killed. Boss L was displeased however, as his friend Ken Hayakawa remained alive. After threatening Hell Dragon's life, Boss L sent him out to go kill Ken Hayakawa. However, Hell Dragon and his gang were defeated by Kaiketsu Zubat, Ken's masked alter-ego.
Later, Boss L sponsored an attempt by the Black Heart Gang to take over a small wild west town by force and build a casino there. Black Star, leader of the Black Heart Gang, arrived in his office to deliver a report on the gang's progress on acquiring the town, but Boss L was annoyed that it wasn't happening fast enough and that Ken Hayakawa still had not been dealt with, ordering Black Star to deal with Hayakawa and get the acquisition done with. However, Black Star and his gang were thwarted by Zubat and brought to justice.