Note: I really want to stress that this theory was developed when there were only 933 chapters so there's very little data out there and any of the claims can be easily overturned by more information.
Lots of attention is focused on Rum or the sister from outside the domain, but not much is focused on Hyoue Kuroda. Here I make 3 possible claims about Hyoue Kuroda. Now I don't expect these to be all correct, but I do feel that they fit the general narrative structure developed by Gosho Aoyama in his previous arcs.
Claim 1: Hyoue Kuroda was put in a coma by Rum 10 years ago and left for dead.
I'm still not entirely satisfied with this theory, since there's so little information, but I definitely think we've seen enough of Gosho's style to make sensible predictions about what he's going to do.
NOVEMBER 2017 UPDATE
Heh completely forgot I made this 2 years ago... I'm still standing by the claims I made back then, with the claims 2 and 3 being further narrowed and collapsed into one claim
Claim 2&3: The Hyoue Kuroda we are introduced to is NOT actually Hyoue Kuroda, but he's actually the father to the Akai family, Tsutomu Akai (who's faking his death).