The Robin Hood actress, who plays Eric Northman's (Alexander Skarsgård) sister on the HBO series, insisted that her character is loyal to her brother.
"She certainly has loyalty to Eric," Griffiths told Collider.
"I think she's actually a very loyal character, but some of her loyalties and trusts are misplaced," she continued. "She's selfish in the way that beings are selfish, but she's not in it for what she can get, to the detriment of people around her.
"She is excited by the prospect of the power that her faith will bring her," Griffiths said.
The 25-year-old went on to speak about her first experience with wearing fangs, saying that her mouth is made for the sharp teeth.
"I know this sounds funny, but I think it depends on how your mouth is shaped," she said. "I don't know whether mine was built for fangs or what, but I didn't have too much of a problem. I did get the giggles the first day I put them in, but they're okay."
> 'True Blood' Lucy Griffiths talks character's "fiery" relationship
True Blood airs Sundays at 9pm on HBO.
Watch a trailer for season five of True Blood below: