'Arrow': Blackstar's Identity Revealed in "Star City Slayer"

While Oliver and Team Arrow were dealing with a killer in the present on Arrow tonight, more secrets about Star City's future were revealed -- including a pretty big reveal about the mysterious Blackstar.

Spoilers for tonight's episode of Arrow, "Star City Slayer", below.

In the 2040 flash forwards in tonight's episode, Dinah, William, Zoe, and Roy went to the remains of the Arrow bunker only to be ambushed by Mia/Blackstar and Connor Hawke. While Mia attempted to get the Archer program codes from William and Zoe, Connor kept watch over Roy and Dinah. Dinah recognized Connor as Diggle's son, something that served as a surprise for Roy, but the surprises weren't done yet.

While Mia questioned William about the codes, she also questioned what he was getting out of things. It was then that William revealed that he supposed he was simply looking for closure because Felicity was his mother -- step-mother, technically -- a revelation that was clearly shocking for Mia as she clearly had no idea who William was. While this lack of recognition might seem like proof that Mia wasn't connected to William, the present timeline set things up for William to be out of the picture as he ended up going to live with his grandparents due to Oliver not being able to give him a safe, stable, normal life.

However, in the last moments of the episode, the truth was revealed: Mia is Mia Smoak the daughter of Felicity Smoak and Oliver Queen.

The reveal delivers not just on fan speculation that Mia would ultimately end up being Oliver and Felicity's daughter, but also on comments Katherine McNamara made to TV Line recently that a huge bombshell was coming tonight.

"Oh god, just thinking back, there are too many to count," she said. "But I'm in Episode 13 (airing this Monday, Feb. 11) 14 and 15 as well, and there are multiple bombshells dropped from this point forward. What you saw at the end of the 150th episode [with Mia and Connor Hawke locating the decrepit bunker] is just the beginning. It's the tip of the iceberg. Actually, this coming Monday is a huge episode for the future storyline. There's at least one massive bomb drop this Monday."

Now that that bomb has been dropped, only time will tell just how Mia factors into things -- both past and future.

Arrow airs Mondays at 8/7c on The CW.