With that line, the Star Wars galaxy saw a monumental shift. Darth Vader, who’s greatest purpose in life is to extinguish any existence of Anakin Skywalker from the galaxy, knows that the apprentice of Skywalker, who arguably is his greatest failure, lives.
Going all the way back to The Clone Wars movie, the Jedi Council assigns Ahsoka Tano to be the padawan of Anakin Skywalker in the hopes that having more responsibility will straighten his path and temper his emotions. Little did they know that Ahsoka’s journey would lead to Anakin having more attachment than they even know. Even more so, Ahsoka would make him feel, for numerous reasons, like he was not the Jedi he was supposed to be.
Look back of the life of Anakin Skywalker and one can see numerous instances where Anakin, who wanted to become a Jedi so as to change the galaxy for the greater good, would have felt like a failure while also dealing with great emotional turmoil. He was a slave who dreamed of freeing all slaves. He not only was unable to do that, he also, for a time, saw his friends enslaved on Zygerria. Moreover, the queen of Zygerria makes him think about whether he traded one form of slavery, that of being under Watto, for another, that of serving the Republic. He promised to free his mother; instead he held her as she died both a slave and captive. He murdered a tribe of Tusken Raiders out of anger, causing him to question his place as a Jedi once again.
Further, Anakin had to hide his marriage to remain a Jedi, ergo the two things he wanted most in the world (to be a Jedi and be with Padme) are at opposition to one another. For an already confused young man, this could only torment the soul even more. When Ahsoka is walking away from the temple, he reveals to her that he too has thought about leaving the Jedi order. Clearly the tragedy he has felt and the parts of his life that are not in tune with the “Jedi way” are becoming more and more relevant to him. Seeing Ahsoka have the courage to do what she believes is right while he is on such unsteady ground about where he fits into the galaxy has to be extremely devastating. Keeping this in mind, and considering the mistrust between Anakin and the Jedi Council, it is easy to see why Anakin decided to take to the dark side when he deemed it to be of greater benefit to him.
As he is reborn as Darth Vader, Anakin must do more than extinguish the Jedi and promote the Empire. In order to truly become a Sith Lord,, he must slaughter the memory of Anakin Skywalker even more heinously than he does the children in the temple. With Padme dead and Kenobi in hiding, the discovery Ahsoka comes to the forefront of deleting Skywalker’s existence.
What, then, will the inevitable showdown of the former Padawan and newborn Sith mean to the galaxy? If one looks back on the history of Star Wars, it will likely not be good for the galaxy.
In Episode III, Vader grows more and more powerful as he kills more and more of Anakin Skywalker’s existence. There is the bowing before Palpatine, the slaughter of the younglings, and the battle with Obi-Wan Kenobi on Mustafar. Looking at the latter in isolation, one can see that Vader grows angrier and angrier as the battle goes on. Then, with the infamous black mask now dawned, he becomes strong enough to break out of the operating table when he learns of the death of his wife, who it can not be stated enough had become the essence of who and what Anakin lived for.
Moving years later, to Episode IV, Vader seems to be at his peak. But look closer at what happens after Vader kills Obi-Wan and discovers that he has a son (as is revealed in the Vader comic). He becomes more and more entrenched in the dark side as this happens. Looking at Empire Strikes Back, we see a Darth Vader who is more volatile and dangerous than ever before thanks to being able to kill Kenobi and seeking to bring his son to the dark side. He puts an entire fleet at risk by chasing the Millennium Falcon into an asteroid field for the slightest chance that it might lead to his confronting Luke, who he probably believes to be the last remaining bit of Anakin (remember he does not discover Leia to be his daughter until Return of the Jedi). When Darth Vader kills a part of Anakin, he grows more powerful. When he is seeking to destroy Anakin, he grows in anger. Neither is good for the citizens of the galaxy.
Which brings us, once again, to consider the showdown between Vader and Ahsoka Tano that is sure to come on Star Wars Rebels. In the season premiere of season two, we saw an extremely dangerous Darth Vader as he battled Kanan and Ezra, who as Jedi are a link to his former self.. His anger is so strong as he tries to destroy this splinter of Skywalker that he is able to lift an At-ST off of himself with the Force and basically toy with two Force wielders at one time. Never is he out of control of the situation. True he does let them go, but he does so only to be able to track the rebels and thus bring even more pain and destruction to the lives of these Jedi.
The discovery, then, of Skywalker’s apprentice can but fuel that fire. Darth Vader sees her not simply as a link back to Skywalker, but also as a chance to destroy the greatest link to Skywalker he knows of: Kenobi. Looking back on what we know now of Vader growing more entrenched in the dark side as he kills of the remanent of Anakin, it is a scary thought of what lengths he will go to in order to kill one of the two greatest links he knows about.
When that time comes, and the white sabers of Ahsoka met then ominous red blades of the feared Sith Lord, the battle will be of epic proportions not just because fans have been waiting since the end of season five of The Clone Wars to see the clash. As Dave Filoni pointed out in the Rebels Recon for the season two premiere, Ahsoka would have had a plethora of training fights with Anakin and thus know his style of fighting; so from a technical perspective the fight will likely be spoken of in the same breathes as the clash of the heroes on Mustafar and the battle of father and son on the second Death Star.
More importantly, there is no way that this battle will lead to good things for the galaxy. Obviously we know Vader is not going to be stricken down by Ahsoka, but will the reverse happen? If Ahsoka dies, it will fuel the connection of Vader to the dark side. If she leads him any closer to Kenobi, his thirst for vengeance against his former master will be palpable in every corner of the Force. However, if she does not lead him any closer, that too will fuel his anger because he will know that part of Anakin still exists as long as Kenobi lives. Top that off with a dash of “what happens to Kanan and Ezra” in all of this and we have a view of Vader at possibly his most evil.
Regardless of how this all goes, it will be exciting to digest as a Star Wars fandom. There will, without doubt, be many paths this story could follow, and if we know anything about Star Wars it is that it is ripe for debate. Due to Vader’s prominence in the saga, whatever direction the story takes will inform every film, show, book, comic, and all other pieces of Star Wars canon beyond our greatest imaginations. All, of course, from a certain point of view.