>>40780912Cirno fits better. Boss/mid-boss in various games, got her own game, prominent character in one of the canonical manga (but in her defense you can't have a manga about the fairies without her playing a role somewhere). Even though she isn't seen much official material in recent years, she still gets merch up the wazoo and her themes are constantly remixed.
Megumin from KonoSuba is very much the Charizard of the series. Generally, whenever a girl in a light novel is constantly being pushed into romantic development with the MC, you can blame the editor for pressuring the author to pair them up. It's super obvious because of how sudden the character chemistry shifts gears between volumes. She also has a spin-off LN with three volumes, and it's gotten to the point where the present popularity poll (where the top three get bonus side-stories) has one vote for Aqua counting as five because the author REALLY wants to write side-stories for Aqua. Due to Megumin's dominance in character polls, the author also said "fuck it" and gave Vanir a whole volume if side-stories even though he doesn't come close to being at the top of polls because Vanir's his favorite character.
Now for two subversions that can easily be mistaken as being "the Charizard" of their respective IPs due to their immense popularity despite their popularity being completely organic:
Yuri Lowell, the main protagonist of Tales of Vesperia. Yuri was so dominant in official polls that Namco had to BAN him as a choice in voting.
Mafuyu Kirisu from Bokuben. This is a character that was never meant to be in the running as a love interest for the MC as she was a teacher and wasn't given nearly as much focus as the first three girls established earlier in the series, but she won in the first poll (right) anyway and MASSACRED the second poll (left), having Lando-T usage% of the overall votes. She crushed the polls so hard that her dedicated chapter for winning warped time and space.