@petrichormus: I explained this before. Akutsu and Aoi are essentially two sides of the same coin
- both are able to trigger a reaction in others. For Aku its the Conflict method (negative energy) making other people think "I'll show ya" and for Aoi it's the spirit method (positive energy)
- both apparently came from a troublesome and poor background. I remember a panel with Akutsu talking about "shitty home" which he escaped with football, whereas Aoi's mother is single and running a bar on a shoestring budget.
- Akutsu noticed somehow that Aoi is walking the same path as he is, only with a different outlook. It's like looking in the mirror for him and it freaks him out so much he wants to get rid of Aoi. Kuroko no Basuke named it as well in Takao, who hated Izuki on sight for having the same abilities. Since Prague Akutsu notices it's not so smart to concentrate on Aoi so much, as the hate is detrimental for his own plays
I don't they'll ever go buddy buddy beyond this, but if they can manage to see eye to eye on football, they're a very lethal duo in defense