There are more pictures.
Fusion could be used at anytime, though to fuse pokemon have to have a high affection/affinity for one another (This isn't the same as breeding matches, though) and it's accomplished by a special device that can be worn as a bracelet or necklace, much like a MegaBracelet. Pokemon will become tired after being fused for extended amounts of time, resulting in them needing to rest or recoup at the pokecenter.
Characters will be trainers, though I'm not opposed to opening up specialized trainers like Scientists and others.
We'll be going through a new Region that seems to be the focal point for Pokemon fusion.
And as for a story, I haven't EXACTLY gotten the details yet, since this is an interest check, but I like that you guys are interested. :3
ALso, more art: