If you would have told Mercury that his name wasn't always Mercury, he wouldn't believe you, that was until he started having the dreams
Mercury doesn't know when the dream started, but what he does know is that giving him Glimpse it was of a life he might have lived at some point, glimpses of a life well he made a scientist much like Edward is, but he isn't working for his darling scarecrow. no the man he takes orders from is attractive and a conventional sort of way, with his black hair and square jaw, not the sort of attractive Mercury could ever fathom being attracted to, not the intimidating evil presents his darling straw man has
but back on topic the dreams also give him glimpses of working alongside a delicate pretty blonde, a glimpse of a life where his hair is the same shade, not white with pink bangs like it is now
glimpses of a life where his name started with a J and not an m, these memory glimpses are not always so mundane some glimpses give him a peek into what made him the thing he is today
animal DNA being pumped into his body, his leg muscles burning to move, to run, to jump, test being done on him by a man he now knows as his coworker
and the moment that he stopped seeing himself as the man with the J name, the moment when he laid his eyes upon his beloved, his mind it already been ready to break from what felt like eternities of solitude and experiments, and when his eyes fell up all the monster he now loves the mind of the man he used to be crumbled Into Love Sick dust, and all you could do was laugh and be mad and in love
Mercury knows now who used to be, but to be honest... He doesn't care, he doesn't want his old life of boring monotony and peace, he loves his new life of chaos and pranks and villainy just too darn much to ever give it up
he likes annoying Eddie too much, he likes tormenting the scaly pushover too much, he likes using his ax too much , he likes loving his boss too much, to ever ever want to be the person he was before
so if you ask him, Jervis is dead and it's better that way, he likes being Mercury far better than he did being jervis, and he's never going to let anyone try to make him be that person again
and even if they did he sure was out of doubt in his mind that his darling master, would come pluck him from his boring life back into his fun life that he never ever ever ever ever ever ever wants to leave
so he's fine with the dreams, they're just dreams after all, and as much as he's concerned he's always been Mercury somewhere deep inside himself even back then