KH3 spoilers: Vanitas localization comparison (Relevant dialogue)>>
I'll only be noting the things that deviate enough or are interesting. Sentences that are 1:1 (or just sounds) won't be listed here. I've only taken scenes that highlight him or his personality, but feel free to let me know if I've missed a bit somewhere.
Listed as ENG between quotation, then JPN after >>
"Who are /you/?"
>> "Who is it this time."
"Gotta say, that strange facade had me fooled at first, brother."
>>"My bad for not realizing it was you with that strange appearance, brother."
"Wait a sec.."
"My heart is made of just one thing."
"My heart is made up purely out of negative emotion." (his heart is negative emotion in itself)
"You insignificant speck."
>>"Remnant of my heart."
==Waking up Ventus===
"So Venty-Wenty wants to keep sleeping."
>>"So Ventus really doesn't want to wake up, huh."
"What am I ever going to do with you."
>>"What a bad brother I have, how it pains me."
(it's "not very smart" of him to stay asleep, silly almost, and it "troubles" him.)
"You better settle down there, "Master"."
>"This "Master" here is quite the hot-blooded one, huh."
"I'm just certain that he'll come to visit."
>> "I'm looking forward to our next reunion."
==after final battle==
"I'm the piece of Ventus that was taken away."
>> "I embody what's missing [lacking] from Ventus." (You could say he is Ventus' "missing piece")
"And you're the piece Ventus needed to be whole again"
>>"[and] you're the one who carried [housed] that Ventus' heart."
"So...why shouldn't you and I look exactly the same?"
>>"That's why my appearance has taken shape after you."
"you define me, Sora, in the same way Ventus does."
>> "Ventus, Sora, I'm built up out of both of you."
"We are brothers who, together, make a greater whole."
>> "Because we are brothers who complement what another lacks"
"Then why won't you stand by our side?"
>> "If you think [feel] that way, then why are you up against us?"
"Instead of with darkness?"
>> "Isn't okay if we just work together?"
"Because I /am/ darkness."
>> "It's my reason for being born."
"And I /do/ stand by your side. I'm the shadow that you cast."
>> "It is /because/ I am darkness, that you both belong to the light, able to exist there."
"How much closer could I be?"
>>If that isn't 'working together' [I don't know what is]"
”To be sifted apart, nice and neat. We should be free to choose"
>>Which one is darkness, which one is light. There's no need to sift it apart like that."
"Not just light, not just darkness. /We/ decide what we are."
>> "I am me. You're you. We can live our own lives freely just fine."
"But...Ventus, I /did/ decide who I am. You see?"
>>Freely-- Well, I am living freely. Like this."
"And what you are is darkness?"
"How is being imprisoned [chained] by darkness anything like living freely?"
(imprisoned [chained] here can be read as physically, but also mentally chained in a way that his mind is made up/bound)
"What I am is darkness."
>>"That's the way of life I chose"
>> "I see."