Here's what happened:
Oda had Yamato planned since Alabasta, Thriller Bark and Kaido's first mention (Ace's vivre Card, chapter 489, and Kaidu the mongol and his warrior daughter). However Naito prevented Oda from showing her earlier, convincing him that it would surprise people and that it would be great to reveal her face in chapter 984 (the opposite of chapter 489 when Brook joined and Ace's vivre card became a plot point) due to number autism. Naito had ulterior motives however, he was really trying to sabotage Yamato in order to favor Kekrot, the underage furry sidecharacter he fell in love with. Naito even went on to rig the worldwide popularity poll to favor Carrot when his plan didn't work out in hopes of changing Oda's mind (he used to have the delusion that Law became important solely because of a dumb poll), and when he realized it might have been too obvious that he was cheating for Carrot he botted Nami twice as hard just to deflect attention away from his shit furry waifu. His plan backfired spectacularly and rigging the poll had the opposite effect: Oda took it upon himself to delete Carrot from the manga in order to teach Naito a lesson.
Naito didn't learn his lesson so out of petty revenge he still pays Carrot shills to derail all anime forums that talk about One Piece. Be it in Japanese or in other languages. They coordinate through discord and other means.
Thankfully Megumi Ishitani, Ryota Nakamura and Tatsuya Nagamine are here to correct Naito's mess