It’s because of this rare material that he winds up face-to-face with Ultron, and that’s ends up not going so well… but beyond that things are evidently pretty good.
As we learned in The Avengers: Age of Ultron, Ulysses Klaue is both an arms dealer and a thief, who happens to specialize in one particular area.
He’s managed to not only regularly escape authorities, but as we’ve seen in various Black Panther trailers, he’s also successfully replaced his missing arm with a new, devastating weapon.
He is one of the only people on the planet to actually see the African nation of Wakanda for what it really is, and his covert expeditions there have allowed him access to the previous metal known as Vibranium.