Why did Vader dislike Krennic?
During Rogue One, we see that Krennic is largely responsible for getting the first Death Star up and running, and that the test they do an the desert planet is completely successful beyond what anyone expected.
Grand Mof Tarkin sees this as an opportunity to make himself look better to Vader and the emperor and decides that he'll take control of the new weapon. That makes sense, as he's looking out for number 1.
Vader also seems to really dislike Krennic, though, and I don't understand why. He sees that Krennic has aspirations for grander things. But the thing is, Krennic gets stuff done. He actually went out and got the resources to build the thing and then built it! It seems that Vader should want to promote him to get more stuff done.
Why does Vader dislike Krennic so much?
Best Answer
As any power-hungry apex predator, he doesn't like others who reach for power, as potential threat to themselves.
This is double-extra valid for Vader, who's working for Palpatine, the latter specializing in pitting his top lieutenants against each other in both Disney and pre-Disney canon.
Vader is intensely uncomfortable with, or rather disdainful of, "mundane" power which isn't of the Dark Side of the Force.
As he told Krennic's successors in A New Hope:
Don't be so proud of this technological terror you created.
The ability to destroy a planet is insignificant next to the Power of the Force.While not stated outright (except perhaps obliquely in Tarkin novel), Vader likely thinks of this to the tune of "If we rely on Death Star, that means the Dark Side wasn't sufficient for the job", and the Dark Side fanatic in him dislikes that implication.
Krennic is an example of those bureaucrats that Vader generally dislikes.
The top brass impression is that Krennic isn't as good (efficient) at his job as they'd like, as Tarkin told him directly (don't recall if that was in novelization only or in the film as well).
While that might be Tarkin's personal power play against Krennic, it likely does reflect Vader and Emperor's view as well, if you recall a very similar dynamics in Return of the Jedi around delays in construction of Death Star II
The Emperor is not as forgiving as I am
Krennic seems to start off with an unhealthy level of LACK of respect for Vader.
He entered Vader's castle with these thoughts (from the official canon novelization by Alexander Freed):
Palpatine had tamed Vader, but he had not created the self-styled mystic and lord of the dead Sith cult.
That gave Krennic hope. If a senator from Naboo could leash Vader, then surely Krennic could as well. Whether he was here for accolades or castigation, he could creep into Vader’s inner circle and break the alliance between Vader and Tarkin....
He's still Anakin Skywalker, and even as a Sith, isn't terribly happy with the idea of killing innocents.
While he's merciless towards rebels, in Disney Canon novel Lords of the Sith we see him openly defy his Master, Darth Sidious, to save the life of an innocent child that the Emperor was about to exterminate.
Remember, his goal is "To bring the Law and Order to the Galaxy" - he sees himself as a Good Guy, not the Evilz for Lulz type like the Emperor.
This bullet is more of a speculation but it seems like a reasonable assumption from what we know in canon.
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Why did Krennic go to Vader?
Krennic was visited by Lord Vader after his investigation on Coruscant and showed him a Ootheca egg that was found in Galen Erso's Office. He told Vader that Erso received blueprints from the Geonosians and that a rogue infestation of Geonosians must have sent him the egg in order to get Erso's help.Why did Tarkin and Krennic hate each other?
Catalyst provides a great background for their rivalry. I don't think it was so much that Tarkin felt threatened by Krennic gaining the Emperor's favor, but more that Krennic was dangerously ambitious. You don't want a person like Krennic, who sees you as a rival, to have the keys to a superweapon like the Death Star.Why does Vader respect Tarkin?
Darth Vader was a Dark Lord of the Sith who only answered to the Emperor and wasn't technically in the Imperial chain of command at all. The only reason he does what Tarkin says is because he respects him as a military leader and was working with him.Why was Tarkin not afraid of Vader?
Yet he kept it to himself, as he didn't care about the Sith or the Force. Although Tarkin didn't believe in the Force, he respected Vader a lot, as he was the Emperor's enforcer, and he even grew to admire Vader's way of inducing fear within others. Grand Moff Tarkin was one of the most feared forces within the empire.How Director Krennic Met Vader for the First Time and was Instantly HATED! (Canon)
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Answer 2
Krennic represents science, logic, technology, the future, which changes and evolves, grows beyond with no limits.
Vader is a sad devotee to an ancient religion who is afraid of being left behind by technology he can't understand, stuck in the past because he has no future.
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