Kuroko is secretly a Ninja.He can turn invisible to throw off opponents and allies. And you thought Ninjutsu (no, not that one) is useless in basketball...
Kuroko dyes his hair.When he was young he started dying his hair blue in order to be more noticable and it actually did help. For an appropriately important game he'll eventually go back to his natural black and be even more invisible than before. (And by extension, he wears light blue contact lenses to match his hair as well.)
- Actually, it's been confirmed that Kuroko inherited his hair color and lack of presence from his mother.
Akashi and Kuroko are related.Pops up a lot in fanfiction for some reason, and they do look pretty similar.
- Jossed, but true in the original concepts for the characters, so it makes sense that it would appear they were related.
Kuroko will go into the Zone against Rakuzan, and use Akashi's skill against him.Akashi's skills would suit a Weak, but Skilled character like him.
The truth about Kuroko backstory that he is going to reveal in Chapter 204 will has something to do with Akashi.Since Seirin will face Rakuzan in the final, maybe Kuroko will reveal something about Akashi (and also he maybe reveal the reason why Akashi has heterochromatic eyes since the they never told us the reason why his left eye colour changed), or the reason he quit Teiko basketball team after they win their third championship. This is just a speculation though.
- First part confirmed; Akashi's left eye's colour changed when he awakened his Emperor's Eye, and the crazier of his Split Personality fully took over him, resulting in the Akashi now.
- Second part confirmed as well.
The reason behind Haizaki's treatment of Kise is because he doesn't want Kise to call him Haizakicchi.Considering that a bunch of other characters also don't like the nicknames he gives them...
The reason Himuro's hair covers his eye is because he has a Sharingan.Remember, characters with hidden eyes have Sharingan until proven otherwise :)
Imayoshi Shouichi is from a yakuza family.
The reason why FIBA suspended Japan...It's not the failure to merge their national leagues into one basketball governing body. It's because the potential Japanese men's youth basketball team would be so overpowered they would beat everybody, including the US and the European countries. I mean, come on, who could beat shooting 3/4 court shots at 100% accuracy? Well, in real life, anyway, since in the KnB universe, it could easily be countered by full-court pressure.