Killmonger was the main bad guy of Marvel’s Black Panther, but the slimy and charismatic arms dealer who helped him out, Ulysses Klaue (played by Andy Serkis) is hard to miss. This isn’t the first time Klaue has been in the Marvel Cinematic Universe, but he’s had a major — shall we say, “upgrade” — since he was last seen.

Want to know why Klaue’s left arm is full of vibranium tech? You’ll have to rewatch 2015’s Avengers: Age of Ultron. Fair warning: It’s pretty brutal.

Killmonger (Michael B. Jordan) is a trained killer with hundreds of confirmed kills as a mercenary, but Klaue is just as deadly. His left arm is mechanical, and comes fully loaded with vibranium tech that lets him fire energy blasts or hack into computers. But Klaue only got the upgrades because his arm was ripped off by Ultron in Avengers: Age of Ultron.

In Age of Ultron, the “twins” — Quicksilver and Scarlet Witch — seek out Klaue, who at the time was just a simple black market arms dealer in the African coast. Klaue was legendary for having successfully stolen vibranium out of Wakanda, which Quicksilver and Scarlet Witch need to help Ultron carry out his grand mission. (The vibranium would come mighty handy later for the Avengers, as it brought the Vision to life.)

In Klaue’s “office,” Klaue sells Ultron the vibranium, but a poor choice of words by Klaue compels Ultron to rip out his arm.

Black Panther Klaue Ultron
He'll... he'll be fine.

It’s violent, brutal, and totally reminiscent of the cantina in Star Wars. It also brings Klaue closer to his comic book counterpart, who has a mechanical arm blaster, but wears a bizarre red spandex with electric blue trimming. Needless to say, Serkis is more fashion-forward in the MCU than he is in the comics.

There’s about a year’s difference between the events of Age of Ultron and Black Panther, but it appears that Klaue wasted no time getting a highly-advanced prosthetic. (And likely paid for it with the fat cash Ultron gave him.) Now, in Black Panther, Klaue strikes up an alliance with Killmonger in a mutually-beneficial mission to destabilize Wakanda. Killmonger wants to rule the isolationist country, while Klaue wants to buy and sell its most precious resource. It’s win-win for both men — that is, if they win.

Spoilers: They don’t.

Black Panther Klaue Arm
Klaw, as he originally appeared in the comics.

Marvel’s Black Panther is in theaters now.

If you liked this article, check out this video: "Marvel Clarified the Awesome Powers of the Black Panther"