We acknowledge that the game is a work of fiction. Historical fiction, but fiction none-the-less.
If every fifth character is also black, I think there is a point that can be made about verisimilitude and taking liberties; but since we know he really existed and that there has been debate on what he did, having a work of fiction that portrays him as a samurai under Nobunga doesn't seem unreasonable.
To compare, we know that Leonardo Di Vinci didn't hand out guns to people or build functional flying machines - but we know he designed all sorts of stuff ahead of its time, so it kinda fits in a fictional story with him in.
But only one of those seems to draw huge amounts of complaints online... And it's actually the less historically accurate one.
British English has a lot more variance than Yankspeak.
We're more likely to use "help V+ing" than "help INF". An average larger vocabulary, atop different usages. Even with US dominated media eroding our dialects faster than ever there's still a lot of difference out there.
I will need a more specific question to give more response. Are you a non-native English speaker living in the UK?