I think I need to summarize how a character can become a videogame character. However, I think it differs for unofficial characters and official characters.
Official characters can become videogame characters under the following circumstances:
- The character originates from a franchise that was originally intended to originate as a videogame. Even if they weren't originally created for a videogame, they are still videogame characters. They can also be videogame characters who have never appeared in videogames before. (Examples: Ash Ketchum, Sally (Sonic), Cylindria (Pac Man))
- The character originates from a franchise that becomes primarily recognized as a videogame franchise (Examples: Geralt (Witcher), Strider (Strider Hiryu))
Unofficial/fanmade characters can become videogame characters under the following circumstances:
- The character originates from a videogame, or they were originally intended to debut in a videogame. As long as the game they were created for isn't based on a non-videogame franchise. (Examples: Psycho Iris (Psycho Waluigi), Rokko Chan, various Sonic fancharacters)
- The character becomes primarily recognized as a videogame character.
So thus, Rokko Chan is a videogame character because she was originally created for a videogame. While in contrast, Meggy (Supermarioglitchy4) isn't a videogame character because she wasn't intended to originate from a videogame. And Meggy, unlike Ash Ketchum, is a fancharacter/unofficial character.