Tonight on the "Arrow" midseason premiere, Oliver Queen vowed to execute justice on Damien Darhk for hurting Felicity. His quest led him to an old foe -- Anarky -- who tempted Oliver to return to his old vigilante ways of killing anyone who got in his way. Felicity's fate was also revealed, as the results from her surgery came back looking fairly grim.

Last time, during the "Arrow" winter finale, Oliver (Stephen Amell) proposed to Felicity at one of his campaign events. On their way home from the event, Oliver and Felicity were attacked by a firing squad that was sent by Damien Darhk. Oliver miraculously survived, but Felicity was left wounded. During the break, "Arrow" ran a few promotional teasers that showed Felicity in the hospital, at one point she even flatlined. With the two previous scenes with Oliver and Barry Allen (Grant Gustin) standing over a grave site, it was speculated that Felicity was going to die in this episode. That however was not the case, as she made it through surgery. Oliver and Barry were still seen standing over the grave in the beginning of this episode, so someone close to them is still going to die. The time card read "four months later," so it's possible "Arrow" won't disclose who died until the season four finale in the spring. Sadly Felicity didn't get off completely scot-free. While she survived her surgery, the team of doctors couldn't fix the damage done to her spinal chord, so for now, she may be temporarily paralyzed. This confirms the rumors that Emily Bett Rickards has been seen on set in a wheelchair. What makes this development confusing is that this sounds like Felicity is becoming the DC Comics character Oracle, but "Arrow" executive producer Wendy Mericle recently debunked that theory. Thankfully Felicity survived the ordeal, and while she may not walk for a while, she's still alive, and that is all that matters.

Because Felicity was so brutally attacked, Oliver set out on a war path to track down Damien Darhk (Neal McDonough). Oliver interrogated Darhk's ghosts, he attacked anyone who knew Darhk's whereabouts, he even put Captain Lance (Paul Blackthorne) in harms way so he could discover Darhk's location. This quest for vengeance led to Darhk's hideout, but some else with a vendetta got there first. Anarky -- Lonnie Machin (Alexander Calvert) -- was back this week, this time to take down Darhk himself. Anarky is a really interesting villain to bring onto the spring premiere, because he held up a mirror to both Oliver and Thea (Willa Holland.) Oliver was letting himself be pushed over the edge by his feelings for Felicity, much like Anarky was pushed over the edge by Darhk. Anarky was also being controlled by blood lust, a desire for pain and death, much like Thea. On tonight's episode, "Blood Debts," both Oliver and Thea had to overcome the anarchy within themselves, so not to fall into the same trap of hatred and revenge as Machin. Machin's blood lust led him to kidnap Darhk's family, who in a twist, Oliver ended up saving. Why did Oliver save Darhk's wife and daughter? Because he knew he had to keep his humanity. As Diggle (David Ramsey) said, there was no point in avenging Felicity if Oliver lost the parts of him that Felicity fell in love with in the first place. Thea also had the chance to kill Machin, to feed her thirst for blood, but she too overcame that desire, and kept a piece of her humanity in tact as well.

Diggle's humanity was also tested tonight when he decided to interrogate his brother Andy (Eugene Byrd) for information on Darhk. Diggle had been holding Andy in the Arrow cave ever since he rescued him from Darhk's ghosts. Unfortunately Andy still wasn't talking, and refused to give up his old boss. When Diggle found out about the attack on Felicity, he took his brotherly gloves off, and beat up Andy. It was only at Lyla's (Audrey Marie Anderson) behest that Diggle talk to Andy as his brother, that Andy finally gave up Darhk's location.

The episode concluded with Oliver saving Darhk's family, Darhk giving Oliver a few months left to live, and Felicity getting an almost clean bill of health. The final scene featured another flash forward, four months from now, with Oliver leaving the grave site and getting into the car with Felicity. Felicity looked like she could barely speak because she was holding back tears. That final scene proves once and for all that it's not Felicity in the grave -- but if it's not Felicity, who is it? Based on her emotional state in the car, I would guess it's Felicity's mom who dies, or someone very close to her. It could be Thea, considering Roy Harper is wearing her uniform in the new "Arrow" trailer. "Arrow's" next episode is titled "A.W.O.L." and introduces a villain from Diggle's past, Shadowspire. Oliver also must get used to a new way of life, which could mean adjusting to Felicity in a wheelchair.