a market 'leader' [=a product or company that is more successful than all competing products or companies]
He is the league 'leader' in home runs. [=he has the most home runs in the league]
He's a 'born/natural leader'. [=someone who has qualities that a good leader has]
(..) to be reckoned with. And Five, as in there's one, two, three, four, five of us. MIA: There was a blond one... Sommerset O'Neal. She was the leader. The Japanese Fox was a kung-fu master. The black girl was a demolition expert. French Fox's specialty was sex. (..)1994 Pulp Fiction