>>2070208Characters from passive media, like shows, comics, novels, and so on, are essentially totems. They are not emmanent in this world, in the sense of being something you can interact with, but exist rather as ideals in the mind that represent sets of characteristics you find valuable. For everyone that likes Miku, there is a Miku that exists for them in their mind.
Activities like idol groups or virtual casting and so on can overlap with this in some ways, since you could say that the essence of an idol is also as someone who represents an ideal of characteristics someone finds valuable (personality is key in the stream game). But it is also different in other ways, because it is someone who is emmanent in this world, out there living life and doing work. Thus, one can say they are a fan of their work, or a supporter of them personally, or an 'oshi', to use the japanese parlance.
