On his recent interview with Larry King, FX "Sons of Anarchy" series creator Kurt Sutter revealed the hardest character to kill off after six seasons of running the show. Now on its seventh and final season, SOA show runner finally revealed that killing Opie Winston, Jax's best friend, is the hardest part of letting go of a character.

There is no doubt that the FX biker drama series is one of TV's most violent shows; people get burned alive, stabbed to death by crucifixes and shot by someone they considered family. When it comes to Opie, he was beaten to death in prison in front of his brothers in the club in the show's season 4.

According to Sutter on his interview with TVLine, he first considered the ending of Opie's character during season 3 and his fate was sealed when his father died thanks to Clay. "I got to the end of that season and realized there is this circular dynamic happening with, and Opie that I felt was very difficult to get out of," Sutter explained.

With Opie's death Sutter is planning something elaborate that will warm up the next episodes of the show. "Jax needed that emotional upheaval, that one event that happens in a mans life that can change the course of his destiny - the death of his best friend was [that]," he continued.

When asked how he delivered to Ryan Hurst the bad news, Sutter disclosed that it's a difficult thing to do since Hurst is so invested to the show and loves his character. But after he explained the reason behind his character's death Hurst understood the importance of his exit in the mythology of the show.

"It's not a death that will happen in vain. Of course there'll be a sense of vengeance, something that drives out guys to retaliate, but also the emotional impact that his death will have on the rest of the characters will always be there," he added.

"Sons of Anarchy" season 7 will be back on FX this September.

See Kurt Sutter's Q & A here.