Darkness is one of the ninja's most formidable weapons.
Most people think of ninjas from the common stereotype as seen in theater.
Actually, They're are not very far off. The people who think of ninjas as brutal, heartless, assassins who just kill either out of cold blood or because they're hired to are far from reality. The first ninja were members of a clan in feudal Japan in the 16th. They thought it be necessary to train under Martial Arts, sabotage, assassination, and espionage for security and protection of themselves and their family. To secure their identity, they wore a black uniform which originated partly from Martial Arts and the idea of the traditional outfit of being black originated from theater.