The following contains spoilers for Black Panther. Feel free to come back after you've seen it.
Sterling K. Brown has a major role in one of the biggest shows on television in This is Us, but this weekend he debuts in what is guaranteed to be the biggest movie in months, Black Panther. Brown joins an all-star cast, but his role, unlike most of the others, was shrouded in mystery, as it was never revealed exactly who he was playing. Now that Black Panther is out, we understand why, because while the role isn't particularly large, it's pivotal to the plot and would have likely revealed story points that Marvel wanted to keep hidden. Read on to learn who N'Jobu really is.
We meet Sterling K. Brown's N'Jobu in the opening of the film. He's in Oakland, California in the early 1990s and he's busy planning something in an apartment that involves the use of a lot of big guns. There's a knock on the door, which turns out to be a couple of Dora Milaje, the female soldiers of Wakanda. Not only that, but they've brought the Black Panther, T'Challa's father T'Chaka, with them.
It turns out that Sterling K. Brown's character is Wakandan, not only that, but he's the brother of T'Chaka. Unfortunately, things are not going well between the brothers, as T'Chaka is there to accuse his brother of working with Ulysses Klaue to steal Vibranium from Wakanda. N'Jobu admits his guilt but argues it's necessary because the rest of the world needs Wakandan technology in order to fight oppression throughout the globe. T'Chaka won't hear it and orders his brother to return to Wakanda to stand trial.
From there the film jumps forward to the current day and follows on the events of Captain America: Civil War. T'Chaka has died and the movie doesn't reference these earlier events until much later. Later, when T'Challa does wonder what happened all those years ago, we get into the serious spoiler territory.
When T'Challa sees that Erik Killmonger has a ring that looks like his, he begins to investigate what truly happened to his uncle. We then see the moments that immediately followed the opening sequence, where N'Jobu pulls a gun on his brother, and the Black Panther strikes back and kills him. We then learn that Killmonger is actually N'Jobu's son who found his father's body and vowed revenge.
We see Sterling K. Brown one final time, after Killmonger drinks the fluid that provides the power of the Black Panther, he has a spiritual vision of his father and the two talk. Both clearly have some regrets about the path that life has taken.
The familial relationship between T'Challa and Killmonger in Black Panther isn't based in the comics, so it's understandable why Sterling K.Brown's character was being hidden, the truth could have revealed this major plot element.