And as for fan art, a lot of companies explicitly allow art based on their IP, as long as it's used/published by the artists themselves and the commercial rights to the work aren't sold to some other company. In Japan, there is a whole industry based around derivative works, Doujin - self-published works, that works off of what is essentially a code of honor. Companies don't go against the artists, as long as said artists adhere to certain guidelines on what they're allowed to depict (eg. no NSFW content.) Many franchises have become a lot more popular due to fan art/derivative works alone (ie. Touhou Project, Fate Series.)