*This flag is not an official flag, rather a combination of the three nation's flags. It was found on the internet and is not the official flag (They didn't have one).
Nazi-Germany
Nazi-Germany was the main attacker in WW2. It was lead by Adolf Hitler and was centered around eugenics. Their goal was to create the perfect human. When they invaded Poland, unprovoked, that lead to the start of WW2.
Italy
Italy was a played a smaller part in WW2. It mainly fought in Europe against the Allied Forces.
Empire of Japan
The Empire of Japan was the part of the Axis that was on the opposite side of Europe. They were the ones to attack the United States of America; bringing it into the war.