Ulysses Klaue was introduced in Avengers: Age of Ultron as a means through which Ultron could obtain vibranium, but Black Panther will see Klaue becoming an official super villain like his comic book counterpart. While Klaue is far from the powerful being made of solidified sound that Klaw is on the printed page, the arms dealer will nonetheless pose a grave threat to T'Challa and all of Wakanda, and the reason he's specifically targeting the African nation is because he views their ways as hypocritical. Andy Serkis laid out his character's basic motivations at San Diego Comic-Con this past weekend, saying:
He is the only person who has been into Wakanda and seen the wealth that it has and he wants to expose that. He believes them to be a hypocritical country. They're playing this kind of 'we're a third world country' card and he knows what's underlying that so he's trying to expose that.
Wakanda is a notoriously reclusive country, and as laid out in the Black Panther trailer last month, not many people outside of its borders know about its advanced technology and wealth. That bothers Ulysses Klaue, who is one of the few outsiders to sneak into Wakanda and make it out alive. That's why, as Andy Serkis told Comicbook.com, he'll try to expose Wakanda's resources and achievements to the entire world, which will subsequently paint a target on those who crave its vibranium and technology. But it isn't just Wakanda as a whole that Klaue hates. He also has a personal issue with the Black Panther himself. Serkis continued:
He is the bringer-down of governments. He collaborates. He's an arms dealer. He knows how to play people and he has a personal vendetta against T'Challa as well.
In the comics, Black Panther and Klaw's adversarial relationship originates from Klaw killing T'Challa's father, King T'Chaka. Since Helmut Zero was the one responsible for T'Chaka's death in the MCU, it's unclear why Klaue has a vendetta against specifically T'Challa. The only potential reason that immediately comes to mind is that T'Challa was the one who branded Klaue as a thief, but trying to bring down an entire nation as revenge seems a bit extreme. Then again, Klaue isn't exactly mentally stable these days (judging by his conversation with CIA agent Everett K. Ross), so maybe in his eyes, that's his idea of proper retribution.
In order to accomplish his goal in Black Panther, Ulysses Klaue will be working with Erik Killomger, a Wakandan exile who is trying to overthrow the Wakandan government. With their resources combined, the two of them will pose the greatest danger to Wakanda yet. And as if Klaue's vendetta and intent to ruin an entire nation weren't enough, he's also use a sonic arm cannon made from Wakandan mining technology, bringing him even closer to the Klaw Marvel fans know from the comics.
We'll see how Ulysses Klaus's sinister plans unfold when Black Panther leaps into theaters on February 16, 2018.