Henry Earl J. Wojciechowski, also known as Hymie Weiss (January 25, 1898 – October 11, 1926), was an American mob boss who became a leader of the Prohibition-era North Side Gang and a bitter rival of Al Capone.
 He was known as 'the only man Al Capone feared'.
The North Side Gang, also known as the North Side Mob, was the dominant Irish-American criminal organization (although a large number of Polish-Americans were members as well) within Chicago during the Prohibition era from the early-to-late 1920s and principal rival of the Johnny Torrio–Al Capone organization, later known as the Chicago Outfit.
Vincent Drucci, also known as "The Schemer" (born Vincenzo D'Ambrosio; 1898 – April 4, 1927), was an Sicilian-American mobster during Chicago's Prohibition era who was a member of the North Side Gang, Al Capone's best known rivals.
 A friend of Dean O'Banion, Drucci succeeded him by becoming co-leader.
 He is the only US organized crime boss to have been killed by a policeman.
Alphonse Gabriel Capone ( ; ] ; January 17, 1899 – January 25, 1947), sometimes known by the nickname Scarface, was an American mobster, crime boss and businessman who attained fame during the Prohibition era as the co-founder and boss of the Chicago Outfit.
 His seven-year reign as crime boss ended when he was 33 years old.
Antonio "the Gentleman" Genna (July 12, 1890 – July 8, 1925) was a Sicilian mobster in Chicago.
 He headed the Genna crime family with his brothers.
 Genna was ambushed by a Genna family turncoat on orders of North Side Gang leaders Vince Drucci and Bugs Moran.
Johnny Jack Nounes, also known as the "Beau Brummell of Galveston", was an organized crime boss in Galveston, Texas, United States, during the early 1900s.
 He, with one-armed George Musey, led the Downtown Gang, one of the two gangs which controlled most of the Galveston Crime Syndicate until the early 1930s.
 They fought for control of the island against the rival Beach Gang led by Ollie Quinn and Dutch Voight.
 As the prohibition era began, his gang came to be one of the dominant forces in the Galveston Crime Syndicate.
 Galveston became the main port of entry for liquor supply in Texas and many parts of the Midwest.
Peter Gusenberg a.k.a. ""Goosey"" (September 22, 1888 – February 14, 1929) and his brother Frank were German-American contract killers and members of Chicago's North Side Gang, the main rival to the Chicago Outfit.
 Peter Gusenberg participated in an infamous attack on Al Capone during a vicious gang war.
The Saint Valentine's Day Massacre is the name given to the 1929 murder in Chicago of seven men of the North Side gang during the Prohibition Era.
 It happened on February 14, and resulted from the struggle between the Irish American gang and the South Side Italian gang led by Al Capone to take control of organized crime in the city.
 Former members of the Egan's Rats gang were suspected of a significant role in the incident, assisting Capone.
Daniel F. Healy (c. 1895 – July 8, 1980) was a Chicago detective who became famous when he killed the leader of the North Side Gang, Vincent Drucci, during an altercation, which occurred during the course of an arrest, on April 4, 1927.
 By 1933 Healy had been made sergeant of the Chicago police
Angelo "Bloody Angelo" Genna (February 3, 1898 – May 26, 1925) was a Chicago bootlegger and organized crime leader during the Prohibition era.
 The leader of his own Sicilian crime family, he was best known for his war with the North Side Gang leader, Charles Dean O'Banion.
 Genna masterminded the assassination of O'Banion in November 1924.

Question: Vincent Drucci was a member of the North Side Gang which was the best known rival of the crime boss known by what nickname?
Answer: Scarface