What belongs in a category is a very debatable concept. Here are some basic rules to follow when putting something in a category:
- In a list of minor characters, a category can only be set if the category applies to every person on the list
- An album inherits all of the categories from each of its songs
- Any page in a series category must be DIRECTLY related to the media of a series (For example Miriam would be part of the Story of Evil category because she was in The Daughter of Evil: Cloture of Yellow, Miriam would not be in the Seven Deadly Sins category because she is not mentioned in a Seven Deadly Sins song)
- There cannot be a category in which there is one member
- For a person to be part of a sin category they must have contact with the sin (For example Kachess Crim had the vessel of wrath, but Elluka would not because she never had the vessel of wrath)
- A song is part of a sin category if the vessel is shown in the song
- A song about a character who had contact with a vessel of sin is not related to the sin unless the vessel was in the song (For example Mikulia Greonio is part of the Sloth category, but Flower of the Plateau is not)
- Sin vs. Time arc
This needs a little more elaborate answer. The largest problem is with vanity and the story of evil. Vanity deals with the sin of vanity, the vessel of vanity is needed for the epitome. Epitome times vary but Riliane's lasted from approximately after the Twiright Prank story to the death of Alexial. Any person who directly influences Riliane after this (for example Clarith) is not related to vanity. The Story of Evil lasted from Anne, and Prim's friendship to the end of Praefatio of Blue (not including the extra chapter). Another examples would be how Five the Pierrot is not sloth.
- For a state/place to be part of a series, one event of the media in the series has to have occurred in the state/place.