If he only turns one black it’s Enma, not Wado, that‘ll change. Enma’s the one that has been brought up as a potential Great Blade that can turn, meaning that is a plotpoint that has openly been addressed in the series. Turning the other swords black so far is just fan speculation.
But it would probably be all of them. Which is kind of a shame because I liked the old contrast where Shusui stood out, but that was thrown away post-skip with Hardening anyway.
But it would probably be all of them. Which is kind of a shame because I liked the old contrast where Shusui stood out, but that was thrown away post-skip with Hardening anyway.