I dunno about Gaijin but they've had you as a "foreigner" in both Revelations and 3, and the Viking one too if you count the large portion that occurs outside of Norway.Nothing wrong with the games and developer can put any race , nationality or gender whatever they want, because it's just a fictional stories based on real life character .
The problem start when Ubisoft or Games media called The person was " A Samurai" in "Real life's " . Which is wrong based on historical data he is just a sword bearer or a retainer or a quire or even a Jesuit follower . https://en.wikipedia.org/wiki/Yasuke
I don't mind the idea's it's actually refreshing and new having a "Gaijin " Foreigner " as Assassins' main characters.