all good quasi-legal things must come to an end
As you probably know if you’ve been reading Inverted Castle for a while, “doujin” (which literally translates to “do it yourself”) is the Japanese equivalent of homebrew comics, video games, and other media, most of which are parodies or homages of commercial works; i.e. “fanfic”. In addition to the gigantic, semi-annual Comiket doujin convention in Tokyo, there are countless other, smaller doujin conventions scattered all over the country and all over the calendar, to the point that a few hard-working “doujin circles” are actually able to make a living off of their derivative works.
Disney, Nintendo, and Konami are the three major companies who have “asked” (read “sued”) not to have their IPs depicted in doujin works, but otherwise copyright owners turn a blind eye to doujin, rightly believing that fanfic is free publicity and good for their business. The doujin work, being unauthorized use of copyrighted works, IS illegal, and the copyright owners could successfully sue them if they wanted to, but the system benefits both parties, so nobody rocks the boat.
That may all be about to change, however, because the Japanese government is considering a revision to copyright law that would give the police the power to crack down on copyright violation, even when the copyright owner does not want to pursue legal action. I’m predicting three results from this change: doujin circles creating their own characters who are just barely different enough from the copyrighted characters they’ve been using, more doujin circles creating their own, original IPs (this is already being done by a few doujin circles like Team Shanghai Alice and Type-Moon with favorable results), and a severe shrinkage of the doujin scene due to these concessions, because many doujin customers seek doujin of specific characters and IPs, and “similar but different” characters and IPs just aren’t gonna cut it.