10 Behind The Scenes Reasons For Star Trek Characters' Quirks
6. Martok Can Never Forgive Kor
J.G. Hertzler had auditioned for just about every alien role in Star Trek before he was invited to come in and read for Martok. He decided that he was going to switch things up, delivering a quiet and controlled performance as the Klingon, instead of the wild, aggressive types he was sure the producers had seen a thousand times before. They asked him to repeat the audition in a stereotypical manner and, having seen his range, he was hired.
In the seventh season, Martok was a well established character and a fiercely honourable man. However, when Kor boards his ship, a new side of Martok is revealed. Suddenly, he seems to have a petty hatred for the older man. The writers decided that Kor would have blocked Martok's ascent through the ranks early on in life, which left the man with a deep resentment. Hertzler felt that this wasn't enough.
He asked to include a line that gave Martok a greater depth. After telling Worf that he earned a battlefield commission, he added 'unfortunately, my father did not live to see that day.' This changes the situation. Rather than Martok's anger and hurt stemming from a purely personal feeling of betrayal, his anger toward Kor stems from his inability to prove his worth to his father.
It was a small change but the addition of the line returned Martok to his honour, gave the two men a deeper divide and helped the audience understand that this man who had been one thing for so long was, in fact, multi-layered.