[Future Rider Prism]

Ok, cool, this is right up my alley!

Here's some possible forms I came up with for Double:

CycloneAccel- Something happens to Shotaro, so Ryu has to temporarily take his place as Double's left side. The problem is, Ryu isn't used to sharing control with Philip, so they have some trouble, and Philip's Memories don't really pair that well with Accel. But until they have Shotaro back, they'll have to make it work somehow.

CycloneNasca- Kirihiko Sudo (the Nasca Dopant) turns on the Sonozakis, like normal, but he knows he can't beat them. So he gives Shotaro the Nasca Dopant Memory, hoping Double can use it against the Museum faction. Philip finds a way to turn it into a Memory that Double can use, bringing them closer to fighting the Sonozakis on even terms. Though, I'm not quite sure what kind of powers Nasca would give them...

EternalJoker- During the Double movie where Eternal appears, he first uses a normal Gaia Memory, but then switches it out for a better one with the same power. In this scenario, Philip takes the Memory Eternal dropped and tries to use it against him. EternalJoker would probably still be weaker than Eternal's stronger form, so Double would have to switch to Xtreme anyway, but hey, they could use it again some other time.

Actually, I might draw these at some point...