Fight! Dragon (1974)

Ryuma Shiranu aka Dragon the last surviving master of the Fubiki Karate Style of karate, and his comic sidekick, Kojiro Musashi travel from Japan to Hong Kong, Macao, Manila and back to Japan fighting the international Shadow Assassins Guild (most commonly refereed to as simply Shadow) whose agents murdered Dragon's mentor. Until Dragons interference they were a well kept secret as they had one rule, no murder must ever even be suspected of being a murder, they must all appear to be tragic accidents or suicides. Committing an obvious murder will result in the assassin involved dying in an accident or committing suicide. Dragon's mentor "fell off a cliff while out for a walk". Which Dragon did not believe for an instant and which led to his discovery of the existence of the Shadow Assassins Guild.