'Arrow': What's Next for Diaz After "The Slabside Redemption"?

Tonight's episode of Arrow ended with a major change in status quo for not just Oliver Queen, but his nemesis Ricardo Diaz as well -- and it's a shift that will have far-reaching implications for the hero.

Spoilers for tonight's episode of Arrow, "The Slabside Redemption," below.

To say that a lot happened in "The Slabside Redemption" would be a bit of an understatement, but it was two events at the episode's end that turned the whole season on its head. Those events? Oliver (Stephen Amell) left prison a free man while Diaz (Kirk Acevedo) was left behind bars and just barely clinging to life. So, what's next for Diaz and Oliver as well?

For Diaz it appears, at least for the moment, that he's in prison and is going to need some time to recover from the fight with Oliver that very nearly ended his life. Despite all his talk about seeing to it that Oliver would die that day it was Diaz who nearly breathed his last so whatever happens next will see the villain needing to recover. Even though he was clearly able to use his influence to turn the guards who drove him to the prison and it could reasonably be assumed that Diaz could do something similar in prison itself, there will be some down time. Given how vicious he came back after nearly being defeated at the end of last season. that down time will likely only make his rage towards Oliver worse.

And that rage might end up ultimately leading Oliver to regret his decision to leave Diaz alive instead of ending him when he had the chance. Amell revealed during a recent visit to the set of The CW series that while Oliver's relationship with Felicity (Emily Bett Rickards) will not be influenced by the sparing of Diaz, it will have an impact on someone else close to him -- and regret is always possible.

"His decision to leave Diaz alive will not influence his relationship with Felicity, but I think it's going to have an incredibly impactful moment on another person that he's very close with," Amell said. "I don't know if he'll come to regret the decision, actually. Probably. Maybe that's part of the new Oliver post-prison, is those are the decisions that he has to live with, even if ultimately the best thing to do would've been to not leave him alive. We shall see."

Which relationship Amell is talking about isn't clear, but one candidate is his relationship with William. Diaz's brutal attack on William and Felicity in the season opener led to William being sent away for his safety. It's something that the flash forwards have shown had a lasting impact so it's likely that Oliver letting Diaz live may have one, too. That impact on the father-son relationship is something that showrunner Beth Schwartz teased in an interview earlier this year.

"Last year we spent a lot of time with Oliver as a father, and those stories were extremely dynamic," Schwartz explained. "Trying to figure out what it's like for a child to have a father who is Oliver Queen has been endless with the amount of stories we can come up with. How that affects a small child with all the trauma he's been through, it's interesting to see how William turns out when he's an adult."

What did you think about tonight's episode? Let us know in the comments.

Arrow airs Mondays at 8 p.m. ET on The CW.