Short answers, pulled from the story.
The Second Italo-Ethiopian War began on the 3rd of October 1935 when two hundred thousand soldiers of the Italian Army crossed the Mareb River into Ethiopia without a declaration of war. This invasion was commanded by Marshal Emilio De Bono and initiated a brutal campaign of aggression that would reshape the geopolitical landscape of Africa.
Marshal Emilio De Bono initially commanded the Italian forces until General Pietro Badoglio replaced him due to slow progress. Later, Marshal Rodolfo Graziani served as the Italian Viceroy of Ethiopia and led the occupation forces.
The Italian Regia Aeronautica dropped over 330 tons of mustard gas on Ethiopian combatants and civilians over the course of four months. This chemical warfare was authorized by Benito Mussolini and implemented by General Pietro Badoglio to target both military and civilian populations.
Emperor Haile Selassie fled the city of Addis Ababa on the 2nd of May 1936 after the decisive Battle of Maychew resulted in a crushing defeat for the Ethiopian forces. He boarded a train to Djibouti and eventually made his way to exile in the United Kingdom.
Over the course of three days following an assassination attempt on Marshal Rodolfo Graziani, Italian forces killed between 1,400 and 30,000 Ethiopian civilians in Addis Ababa. The Italian authorities under the command of Guido Cortese were given carte blanche to destroy and kill Ethiopians, leading to widespread executions and the burning of homes.
The Second Italo-Ethiopian War ended with the Italian defeat in 1941 when Ethiopian forces, supported by the British, liberated Addis Ababa and restored Emperor Haile Selassie to the throne. The war concluded with the Allied victory in World War II, which ended the Italian occupation and restored Ethiopia to its pre-war status.