Accel World/WMG

Crossover WMG: Accel World is the future of Sword Art Online
It's been in the net for months. I just heard it this week. Rumor has it that Snow Black Princess is the daughter of Kirito(SAO hero) and Asuna(SAO heroine). There were also bits in the manga and lightnovel suggesting that it happened in the same world.
 * It makes sense since both settings are written by the same author, and Accel World is set at least twenty years after SAO, with the virtual reality technology in SAO being obvious precursors to Accel World's linkers. Plus, Snow Black's duel avatar has possible shout outs to Kirito, with it being black and having two sword arms as its primary weapons.

Kuroyukihime is raising Haru to reach level 9 so that she can defeat him and become level 10
Kuroyukihime continues standing by Haru's side and helps him fight others, and when he finally reaches level 9, she fights him to gain the level 10 title and the knowledge of Brain Burst's true purpose. It's somewhat possible, based off of episode 3 of the anime. Unless the comic took/takes a different route.
 * Expanding on this, given that you have to defeat 6 level 9 enemies to become level 10, and Kuroyukihime killed the Red King, there are only 6 current level 9 enemies left, including Kuroyukihime. So she's either going to fight him or let him kill her without a fight, meaning that either way one of them loses their Brain Burst, which is (from Haru's point of view) the only reason why they are connected at all. Cue crisis of faith and angst until he realises that Brain Burst wasn't the only thing that connected them.
 * A further note: we'll be able to see what Kuroyukihime has planned depending on who she has inflict the final blow on the first and second defeated kings. If Haru does both, then even if she attacked him at the very end she'd be a lv 9 victory short, and would be stuck as the only level 9 player left, effectively trapping her in stasis. If she kills steals either of them, then chances are she's going to force a final confrontation.
 * Then again, she already has one victory against a level 9 opponent, so it's possible that she'll simply use him to deal with armies while she deals with kings, to ascend as a level 10 with him as her level 9 right hand man.
 * Oh well, given that there's a replacement Red King my previous theory about there not being enough Kings to go around doesn't hold water any more. Still, Haru's promise in episode 8 just seems to shout out to me that they'll be forced into a confrontation at some point.

Akihiko Kayaba is the creator of the Accel World
He managed to find a way to either preserve his consciousness in the net, or left a self aware AI based on his personality somewhere. In either case, Akihiko returns, and the Accel World is his latest experiment to see how its users utilize it.

Princess Snow Black's name is Shirayuki
Because it is a real name, and not that different from Kuroyukihime (take the suffix away and change "Black" to "White"). It's also enough of a change that people wouldn't connect her name with her handle, and "Snow White" becoming "Black Lotus" is amusing enough to fit in.