Ziva killed Ari.
At least, as far as she or anyone else knew, Ziva killed Ari.
Gibbs knew better, as he had known for some time now. Ari wasn't dead, nor would he be dead until some one took his head.
It had to be him, too. No one else. Ari may be a relatively young Immortal, but he was the worst sort: a dangerous bastard whose immortality had gone to his head. He had no fear of consequences to ground his actions or stay his hand. He did as he pleased because he could. He toyed with the mortals around him because it pleased him. He killed them because that pleased him, too.
He killed Kate to prove to Gibbs that he could do whatever he wished; because he knew Gibbs had appointed himself her protector.
He was calling Gibbs out. After all this time, after all these months of cat and mouse, Ari thought he was ready to end it.
He hadn't counted on Ziva pulling a gun on her 'brother' or even pulling the trigger. That much unpredictability had never figured into his grand plans to make Gibbs suffer and then take his head. It had been his fatal flaw in the end, his arrogant assumption that he could do no wrong or that his plans were golden.
Gibbs knew it would not end with Ari's 'death.' Which was why, while everyone was taking those first breaths of free air after holding it in for so long, he was sitting on a stool in Ducky's autopsy room, waiting. While everyone else was mournfully saying good-bye to a friend and colleague, he was preparing to avenge her death.
He was preparing to see this through to the bitter end. And while it wouldn't be the honorable duel to the death that he'd been trained to deliver, it would be exactly what this duplicitous snake in the grass truly deserved.
Waiting had never been Gibbs' thing, though, and after a while, he grew impatient for the moment to come. He got up off the stool, and stalked to the freezer drawer where Ducky had stowed Ari's body hours before, where it was to remain while transport back to Israel could be made. He pulled the drawer open and looked down upon face of his enemy.
Ari was pristine in death, laying cold and still, his once grievous wounds almost healed now. Life would be returning to the body at any moment. Ari's eyes would open. Gibbs wanted to be the first thing - the only thing - he saw when they did.
He wanted Ari to know who was taking his head - whose sword glimmered and flashed in the sterile room as it arced downwards towards he neck.
Ari's eyes opened at last, and they barely had the chance to register this knowledge before Gibbs's sword sliced through his neck. Gibbs braced for the Quickening.
******
"So, you've taken his head at last."
Fornell was waiting for him when he returned home. Even though it was late and Gibbs had stayed to clean up the utterly destroyed autopsy room, he was not surprised to find the FBI agent occupying a chair in his sitting room.
"You knew."
Gibbs was the first one to talk and it was a hate-filled accusation that fled his lips as soon as the door was closed.
Fornell shrugged, as if to say 'I might have' but he didn't actually say anything. He was too busy eying Gibbs like a hostile. Which was a good thing, too, because right now, Gibbs felt the same way about Fornell.
"You knew, and you did nothing to stop it," Gibbs continued. "He killed Kate, damn it, and you did nothing! And you KNEW!"
His voice was climbing higher and higher and Fornell had the sense to take a step back. "Agent Todd's death was unfortunate, Jethro, but not -"
"No! Damnit, no, Tobias! Kate's death was most emphatically NOT unfortunate. It was undeserved and easily preventable, if you had listened to me instead of harboring that monster!" Gibbs took a shaking breath, but continued to glare at Fornell. "Who else knew what he was?' he asked at last.
"Just me and a few others," Fornell answered, assuming Gibbs meant who else in the FBI and Mossad. "Everyone else just thought he was a double agent. They thought they could use him to -"
"Yeah, well, that's where they screwed up, wasn't it? Thinking they could control a hostile and insane man for their own ends. It doesn't work that way," Gibbs shot back.
"Doesn't it? He would hardly have been the first of your kind to give their loyalty to a government or a cause," Fornell said, looking pointedly at Gibbs himself as if here was all the example he needed.
"We're not all alike," Gibbs spat back, "so don't ever compare him to me again. Ari was a trained killer and a trained liar long before the death which confirmed his Immortality." Gibbs laughed bitterly. Director David thought he was raising the perfect weapon, a double agent who would work for him and carry out any order he was given with loyalty and zeal. Instead, he had created a monster with a God complex, a heartless, sadistic killer who did as he pleased because nothing the mortals would do could actually harm him. He couldn't be chained by laws which no longer applied to him.
"He had no loyalty, Tobias, save only to himself," Gibbs said, sadly. "I tried to tell you that once before. If you hadn't been trying to play your own games, you might have realized I was right."
Fornell shook his head. "When you play with fire, sometimes you get burned," he said in a sorrowed tone of voice that echoed Gibbs' own.
"Or other people do, so don't rationalize it any other way." Gibbs could see that his 'friend' was trying, but he was still angry, still worked up about it. Innocent people had died. Kate had died. And all for what? Because someone in the government had thought they could control an Immortal who had no soul. Someday, soon, they would have to talk about that, too. How Fornell knew what he knew. Who else knew.
But not tonight. Tonight, all Gibbs wanted to do was raise a glass in honor of Caitlin Todd, who had been a good agent, a great friend, and an exceptional human being.