Will Oliver Go Back To Being A Killer on 'Arrow's Season Finale?

The Black Canary (Caity Lotz) gets ready to kick some butt in this new still from the season finale of Arrow.

In “Unthinkable”, Slade (Manu Bennett) moves forward with his plan to kill one more person in Oliver’s (Stephen Amell) life. While Oliver has fought all year to be more than the killer he once was, when Slade kidnaps someone close to Oliver’s heart, Oliver is pushed to the edge and realizes sometimes it takes doing the unthinkable to stop the monster.

Meanwhile, Diggle (David Ramsey) takes on Amanda Waller (Cynthia Addai-Robinson) with a little help from some friends, and Thea (Willa Holland) turns to Roy (Colton Haynes) in her time of need.

“Unthinkable” airs TONIGHT @ 8PM ET/PT on The CW. 25+ pics inside…