This is render of the artist's original character. While their skin tone does seem lighter here, evidence of prior work featuring this character (such as here: post #2616650 or here: post #2560761 ) suggests they do in fact have a darker complexion. This would imply a dark_skin tag. However danbooru's guidelines on such is unclear to me at this point, in that I'm unsure if we still tag what we see, or what we know. Therefore, I won't be re-adding the tag but if anyone else sees fit to do so, i don't feel it should be objected to without clarifications on the objection.
I would go by "Tag What You See". It's important that users are able to find pictures based on the content of the image. I've had instances where I wanted to find an image back and searched, based on what I could remember in the picture, without finding it anyway through those means. When I DID eventually find it back through a lot of digging, I noticed many of the tags that i was searching for, which were the most prominent details I remembered, weren't even added as tags. "Tag What You See" is a big deal.