By Ryan Rigley

With Slade Wilson's army out for blood, Team Arrow must band together with the League of Assassins in an attempt to save Starling City from burning to the ground.

This week's explosive season finale, entitled "Unthinkable," sees Oliver Queen faced with an important decision: to kill Slade or not to kill Slade. As Felicity urges him to take the high road, Oliver comes up with a plan to outsmart Slade once and for all.

Here are the biggest highlights from this week's "Arrow":

Red Arrow

As Roy Harper finally wakes from his venom-induced coma, Oliver hands him his very own red mask. Now that the Mirakuru has completely left his system, Roy is looking a little less like Arsenal and a lot more like Red Arrow. In fact, this episode marks the first time that we've seen Roy successfully taking down enemies with his bow, as opposed to just punching them through a window.

Diggle's Baby

When Dig and Lyla storm into A.R.G.U.S. headquarters, Amanda Waller reveals that Lyla is pregnant with Dig's child. How will this affect Dig's role on Team Arrow? Now that he's going to be a father, perhaps Diggle will have to bow out of the vigilante business and let Roy Harper have his time to shine.

Passing the Torch

As agreed upon at the beginning of the episode, Sarah leaves Starling City to rejoin the League of Assassins; but not before handing her Canary jacket to her sister, Laurel. Since Laurel now knows Oliver's secret and has successfully proven herself on the battlefield, it seems like there's a pretty good chance that she will be taking up the mantle of Black Canary sooner rather than later.

Thea Merlyn

Finding Roy's secret stash of bows and arrows, Thea ultimately decides to leave Staring City with her real father: Malcolm Merlyn. How will this come back to haunt Oliver and Roy? Something tells us that the next time we see Thea in Starling City she'll be a bloodthirsty assassin on a quest for vengeance.

Wall of Secrets

In the very last scene of "Unthinkable," we see Oliver Queen waking up in Hong Kong and being introduced to Amanda Waller. While we already knew that Oliver and Amanda had met prior to this season, we still have yet to discover what role Amanda plays in getting Oliver back to Starling City. What other secrets about Amanda Waller are being kept from us? Guess we'll just have to wait until next season to find out!

What did you think of the season finale? Let us know in the comments below.