Originally Posted by Dark Raven
An Essex accent isn't the only British accent. There are huge variations across all the counties. If he's attended Oxford, or brought up in a boarding school or private school, he shouldn't sound like an Essex lad at all. Not that I really want him to have a British accent anyway. But the point is that if he is a king and can afford to be educated in England, he wouldn't sound like a commoner and wouldn't pick some local comprehensive school.
"Essex" was just ignorance on my part, I should have stuck with Oxford. I didn't realize the received pronunciation doesn't necessarily come from anywhere, per se.
I personally would have him school in the states to be more immediately identifiable to American audiences, though England wouldn't exactly hurt that. Other than that, I view the opening pretty much the same as you do.
And a lot of the African accents aren't far from British accents as far as the endings of words. Some of the hard consonants are different, especially that Zimbabwe area, but by and large, not a big leap. You could effectively split the difference for the two and harden the sounds to A) Create a brand new African sounding accent and B) Illustrate, even in the accent, the "dichotomy" of Wakanda, both very advanced, and very African.