The character in question is based on Miku and is basically her with an alternate costume and color. The artist even says as much.
Moreover, artist commentary and Pixiv tags don't necessarily conflict with "no metaknowledge" or the "tagging rules of Danbooru", as CDP5280 puts it, since both are sometimes used to tag or better understand an image. But he and a couple others disagree, so I want it settled.
Updated by user 143344