Metal Sonic never believed he could have emotions, he wasnt ever programmed that way, but after dimensions intertwined and he met Chaos Sonic, something within him changed, and now he wasnt sure what was real or fake
A young girl gets caught in a split dimension. Another time, another feel, no identity.
When She wakes up (Sienna) in her own home, world, different time, nobody else left, she is completely isolated, as so she thinks.