Thea Queen (Willa Holland) has been away for a while on Arrow, but returned last week for Specter of the Gun. She's also only suited up a couple times this season, spending most of her time handling issues in the Mayor's office. But Oliver's sister will be getting a lot more to do in the back half of the season, executive producer Wendy Mericle told EW.com:
She's headed in a direction that's very similar to where her mother was before she was killed in season 2. I'm actually really excited about her storyline, because we're taking her to a place where she's been dealing with all of these issues the same way Oliver has, with her bloodlust and with other elements of her past, and this season's going to find her in a similar place, but for very different reasons. There's gonna be a great scene coming up between Oliver and Thea that's one of my favorites on the show.
That's pretty cryptic and it has appeared that Thea had quelled her blood lust and no longer had the killer instinct. Are we looking at a return of the effect from the Lazarus Pit? Thinking back to where Moira Queen (Susanna Thompson) was just before she died, she seemed to be trying to make amends for her past and come clean to her children. It would be nice to see the character step out and stand on her own instead of being Ollie's shadow in and out of costume.