User blog comment:Trainer Micah/Pokemon Sun/Moon prediction's 4 Anime/@comment-4990633-20170521161409/@comment-26573805-20170601184815

His partner Pokémon since the first episode of the anime has been Pikachu all along. That's what it's referring to - the main Pokémon owned by the character. And it didn't refer to any other Pokémon in the summary that is seen on karubii's twitter account.