No, if an artist doesn't get it at some point, art of that ninja from The Bouncer will appear and throw a wrench in the works. Best not to invite the later annoyance.
Posted under General
I highly doubt Mugetsu from the Bouncer will show up, and if it did (which would likely only be official artwork) it would be at most like 3 images. The Bouncer is an old game, 10 years old now), and there does not seem to be any real interest in it. If you search it up on pixiv you'll have less than 2 pages of content, and several of the images are of big daddy's from Bioshock. If the main cast is barely getting any fanart, then a minor character like Mugetsu is going to be even rarer.
I'm also not quite sure why we should reserve the tag for an artist as opposed to a character. After going over the numbers, there doesn't seem to be a significant reason to favor artists over characters.
Total artists: 59171
Artists with over 20 images 7865 (13.29%)
Artists with over 10 images 12900 (21.80%)
Artists with over 5 images 19292 (32.60%)
Artists with 5 and under: 39879 (67.40%)
Total characters: 43292
Characters with over 20 images: 6122 (14.14%)
Characters with over 10 images: 9926 (22.93%)
Characters with over 5 images: 14648 (33.84%)
Characters with 5 and under: 28644 (66.16%)
The character from Touhou already is in the upper 14.14%, the likelihood that an artist would come around and have the same tier of images is only 13.29%. If you want to get more specific, only 5.10% (2207) of characters have 69 or more images. The percentage of artists having 69 and more images is only 3.84% (2274). All values are from the tags tab. So even if an artist does appear, it is much more likely that the artist will have fewer images than the character. Reserving it then for them seems rather pointless.