Kang chews out Kirk. The Enterprise attacked his ship, unprovoked! Suddenly, Chekov accuses the Klingons of killing his brother, Piotre. Kang instructs his men to use the Agonizer on Chekov, forcing Kirk to surrender. But when Spock transports them all onto the Enterprise, he holds the Klingons in the transporter beam until a security team can arrive to capture them.
Kang was played by Michael Ansara who passed away a couple of weeks ago. Below is an animated gif made from the screen shots I used from the episode as reference.