He was the founder and one of the leaders of the armed wing of the African National Congress (ANC), also known as uMkhonto weSizwe (MK). They mainly did things like sabotage government buildings by destroying electrical substations, or detonating car bombs to kill government security/military. They would also burn down farms. They absolutely killed people and Nelon Mandela was personally part of the planning and execution.

They did this as part of an ultimatum against the South African government to end apartheid through constitutional amendment or the campaign of sabotage would continue. Mandela was a hero and should be remembered and venerated as such.