Yeah, it seems kind of silly for someone to be offended by a black character being referred to as black. o.O (But still, good to have checked before posting, just to be sure.) There's not really any other word you could even use. African-American is wordy, and kind of silly when, well...none of the characters are American. And America doesn't exist. Or Africa, for that matter. (Now, if the real-world continents do exist in your Pokemon World, that's different, but the characters still are probably not American.)
It gets interesting when we consider other races, though. "Black" and "white" are just colors, and work fine in a fantasy world, but what about geographically named races? You can't very well call someone Asian in a world that has no Asia. It makes even less sense when you consider that being an anime, the majority of the characters in Pokemon are supposed to be Japanese (or...y'know...the Pokemon world equivalent thereof) so being Asian would be the majority in that case (if you have a story set in Japan, it's kind of silly to point out that a character is Japanese. They all probably are.)
I ran into this problem in my fic several revisions ago. I had a character based off a friend of mine who was Hispanic, and originally I described him as that. Then I eventually decided that within the context of the Pokemon world, that was kind of dumb, and just went with a literal description (tan skin, dark hair/eyes.) It's not
as descriptive because it doesn't give the same kind of facial structure information, but I figure it works. So now I tend to go with literal descriptions for all races and if someone is fair-skinned, say so, and if someone is dark-skinned, say so, since using the real-world terms just feels off.
~Chibi~

