I am here by dubbing 2013, 2014, and 2015 the Sonic and Mega Man Crossover Saga: 2013 had Worlds Collide comic crossover, 2014 had the two as fighters in Smash Bros 4, and 2015 is gonna have another comic crossover known as Worlds Unite.
What do we know at this time? None thing other than it's gonna be a bigger than Worlds Collide
I'm wondering if we're the Archie exclusive characters are gonna appear in it this time (Though Sally and Snively had cameos in the Worlds Collide since Xander Payne is likely gonna play a big part in the cross over this time (Issue 40 of Mega Man had him see the events of Worlds Collide, an event where none of the Mega Man cast remembers happening). What he has planned? My guess is that he's gonna alter the time lines, or the events of Worlds Collide, and try to take out both Mega Man and X, or maybe he plans to trick all three of them into fighting each other (Remember, none of the Mega Man cast remembers Worlds Collide). Though we will see, more details about the crossover will be given out later this week, so we won't have to wait long to see what's gonna happen. Until then, I'm gonna play SUPER SMAAAAAAAAAAASH BROTHERS 3DS!