![1girl black_cardigan black_legwear brown_skirt cardigan character_request closed_mouth collarbone copyright_request ear_piercing eyebrows_visible_through_hair flower full_body highres kneehighs long_sleeves looking_at_viewer namori neckerchief piercing pout pouty_lips short_hair sitting skirt sleeves_past_wrists solo white_hair yellow_eyes yellow_neckwear rating:s score:5 post #3828569](/cdn_image/preview/29/bb/29bbce7c20d2f8cf857ab7e25a1aac92.jpg)
As it's name implies, this tag is used if a copyright from which a character comes from is unknown.
If it is known that a character doesn't come from an established copyright, then use the original tag. See the wiki page for original for a list of Japanese tags that indicate an original character.
The following tags are aliased to this tag: /copy and series_request (learn more).