Responses
They gave him a collar cuz he has brown (well gray) skin
Honestly, that didn't cross my mind at first, I'm very into Femdom/malesub so I read a lot of it and I have seen many with a guy wearing a collar on the cover, so I thought this one would be just one more like that. But I can see what you mean now, he's a servant so having him being dark skinned and wearing a collar is really weird, especially considering he seems to be the only dark skinned mc in all of this author's works.
Bc of the name and the fact that the guy is wearing a collar I was expecting Femdom/malesub content, but it was just plain heteronormative porn. Good for those who enjoy it I guess, but to me it was just boring.