Fancharacters

From Kokorodatabase

Characters in works like fanfiction, fanart, or roleplaying games that weren't created by the makers of the original series. While whether or not some of those characters could be considered Mary Sues is debatable, these characters were created by their fans; hence their name. Some authoresses object to the term and prefer their characters to be called 'Original Characters' (OCs).

Examples of fancharacters include Kitenshi Kocha, Kuroneko Satou, Bob Pushkaboomda, Nakagawa Daichi, and Shinga Shikari.