Black Shadow is a Decepticons mercenary and gangster whose skills in robbery, extortion and murder are available to anyone who can meet his price he is only loyal to the highest bidder even his fellow Decepticons don't like to work with him as they are afraid he'll betray them mid job if he gets a better offer.
Despite all this he is one of Megatron's "phase sixers" of Megatron's planet infiltration protocol phase sixers come down and destroy everything in the way of Decepticon conquest Black Shadow does this by transforming into jet mode and devastate buildings around him with powerful sonic shockwaves by breaking the sound barrier while flying at low altitudes.
Black Shadow sometimes appears in Transformers comic books/video games/animated series as either canon fodder, a minor villain, or a small cameo.
Powers & Abilities
Naturally, as a Transformers, Black Shadow is immensely large in size, and possesses super-strength. He, however, can also shoot powerful blasts from his giant gun-like cannon, and can shape-shift into a jet to fly.