The protagonist of another novel by this author runs away from one woman that he has been living with after he overhears Shizuko and her daughter Shigeko playing with a rabbit that they intend as a gift for him; the protagonist of that work by this author questions if "immaculate trustfulness" is a sin after his friend Horiki shows him a shopkeeper raping his wife, Yoshiko.
In one work by this author, a group of revelers get drunk to chants of "Guillotine, Guillotine, Shooshooshoo"; one of those revelers is a man the narrator refers to as M.C., which changes from "My Chekhov" to "My Child" to "My Comedian" in a series of letters. The protagonist of another novel by this author runs away from one woman that he has been living with after he overhears Shizuko and her daughter Shigeko playing with a rabbit that they intend as a gift for him; the protagonist of that work by this author questions if "immaculate trustfulness" is a sin after his friend Horiki shows him a shopkeeper raping his wife, Yoshiko. Yozo first attempts a love suicide with Tsuneko, before becoming an alcoholic and morphine addict in one novel by this author; the novelist Uehara fathers a child with the narrator on the same night that Kazuko's brother Naoji is killing himself in another novel about the postwar fall of an aristocratic family. For 10 points, name this author of The Setting Sun and the I-novel No Longer Human. 
In one work by this author, a group of revelers get drunk to chants of "Guillotine, Guillotine, Shooshooshoo"; one of those revelers is a man the narrator refers to as M.C., which changes from "My Chekhov" to "My Child" to "My Comedian" in a series of letters.
Dazai Osamu [prompt on "Osamu"]