1. Albert Anastasia, murder inc, responsible for 400-500 murders.
2. Al Capone did personally commit few murders himself but he was responsible for over 300-400 people's death.
3. Roy Demeo killed criminals and civilians, 100+ people killed by him and his crew.
4. Greg Scarpa killed 60-100 people.
5. Tony Mirra is responsible for killing 30-50 people both criminals and civilians he killed that's for sure.