Why did Sailor Moon end up being the main character when Sailor Venus was the original main character?

Answer 1

While it is true that the Codename: Sailor V manga debuted before the Bishoujo Senshi Sailor Moon manga did, the anime series of Sailor Moon always had the titular character be the main character, or protagonist. Furthermore, the Sailor V manga was originally meant to be a oneshot, rather than an ongoing series, and there had been no expectation that it would spin-off the mega-hit series that Bishoujo Senshi Sailor Moon became.

The Codename: Sailor V manga was also not finished before the Sailor Moon manga debuted; it ran in a different magazine (RunRun) while Sailor Moon ran in Nakayoshi, and at a slower pace. Despite it being shorter (3 volumes in its original release, 2 in its new-cover format, which is the version finally licensed by Kodansha USA for release in English-speaking countries), the final arc of the Codename: Sailor V manga did not appear in print until after the Sailor Moon series ended.

In the manga, Sailor Venus is still regarded as the leader of the Inner Senshi (comprised of Sailors Moon, Mercury, Mars, Jupiter, and Venus), while Sailor Moon is Princess Serenity, and the one with whom the other Sailor Senshi are charged with protecting. It is because of her leadership that she is able to wield the Holy Blade in the first arc of the manga, using it to kill Queen Beryl.