As all Arrow fans know by now, Oliver's nickname for Thea is "Speedy." However, what some of you may not know is that in the DC comics that particular nickname was affiliated with Roy Harper.
The moniker Speedy was passed down to another sidekick of Oliver's when Roy became Arsenal. That person? Mia Dearden. Thea's full name is Thea Dearden-Queen and whilst in Corto Maltese she went under the name Mia. Obviously making her, Mia Dearden-Queen. Combine that with the training Malcolm Merlyn has been giving her, and the latest events in the most recent episode...
The Flip Side
Despite the nickname and the name-switch, there is a chance she may even become Artemis...
A little background on Artemis' similarities with Thea
Artemis' father is an assassin with ties to the League of Shadows just like Thea.
Artemis opts for a life of good, but not without a dark past, and becomes Green Arrow's apprentice again, pretty much sums up Thea, now doesn't it?
If she was Speedy, a lot of people close to Ollie and Thea would begin suspecting Ollie and her of being the Arrow and Speedy duo really quick... Maybe it's not the best idea to make your nickname your superhero name after all.