The latest trailer for YouTube Red's upcoming Cobra Kai series shows William Zabka's Johnny as a ruthless sensei.

"I'm going to teach you the style of karate that was taught to me. Fear does not exist in this dojo, does it?" Sensei Johnny asks a student, calling back to the Cobra Kai mantra he obeyed as a competitive teen in the 1984 film The Karate Kid.

"No, sensei!" his follower barks back.

"Pain does not exist in this dojo, does it?" Johnny challenges another group of students.

"No, sensei!" came the response.

"Johnny Lawrence is still fighting his old nemesis Daniel LaRusso. Rivalries never die, even 30 years later," said a message accompanying the 30-second preview, which does not show Ralph Macchio reprising his role of the balance-seeking good guy Daniel.