Sakunosuke Oda

Was a member of the Port Mafia. Oda was a man described as kind, despite working for the mafia, by Dazai. He had an incredibly perceptive side to him that allowed him to come the closest to understanding Dazai, whom he referred to as "his dear friend, who had grown tired of the world and is simply waiting to die."

It is his understanding of Dazai's loneliness, as well as his regret of not being able to do anything about it, that prompted him to leave behind the last words that became the trigger for Dazai deserting the mafia in favour of carving a brighter path for himself, something that Oda wanted to do.