Parrack's character Hoyt recently split up with Jessica (Deborah Ann Woll) after discovering that she had slept with someone else.
Parrack has now told New York Magazine that Hoyt could take a turn for the worse if he finds out that Jessica and Jason (Ryan Kwanten) are interested in each other.
"Hoyt's father is dead and gone," he said. "His mother is dead to him. So he only has two people left - the love of his life and his best friend. And if they're gone, what is there? That's the kind of thing people kill people over, or destroy their own lives over.
"Hoyt is somewhere between those two poles. He has nothing now. People took him for granted and misused his love. So I think we're just barely scratching the surface of how dark he can go."
Parrack added that Hoyt's sensitive side means that he could be even more dangerous, saying: "There's something about people who are so loving that when they snap, it's no joke. There are definitely some volatile moments coming up. It's not going to be pretty."
True Blood, which was recently renewed for a fifth season, continues on Sundays at 9pm on HBO.
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