Yep, Sagramore. In the Matter of Britain Arthur does have Moorish/Saracen knights at the Round Table, but Sagramore himself isn't one of them (Moriaen is the Moor and Palamedes the Saracen IIRC), being Hungarian instead - I think Cornwell just condensed these 'foreign' knights into one guy for convenience's sake, and went with the most plausible ethnic background for a darker skinned dude in Dark Age Britain (the Hungarians wouldn't come to Europe for centuries later). And to be fair, the Mauri (original, Christian Moors) were both very real and a significant element to the late Roman imperial cavalry.

But man, this series clearly fucked everything up in usual DEI fashion. And not just that, but they seem to have not even tried their hand at the slightest pretense of an authentic late Roman/Dark Age setting. What the hell even are those black outfits on the guys in the article's photos? They look absolutely nothing like Late Roman/Romano-British civilians or soldiers, much less barbarians of either the native Celtic or invading Anglo-Saxon varieties. End stage GoT's fashion direction of overly dark and modern-looking outfits for everyone has been a disaster for the depiction of historical fashion on screen as much as woke racial politics have been for anything resembling accuracy in the ethnic makeup of every historical setting adapted to screen.