Zephyr0010

You could use a multiplier for the dagger with the standard effects, and one for the curse. The curse could have the disadvantage for a charge pool, starts at zero, requires multiple charges and recover a charge on draws blood (does body). Might require GM permission (little hazy one multipower and charge rules)

Im sort of new to the game but could you set it up like this: Duplicate ( limited to only one of, say 50 cp? to be normal ish) game starts with a duplicate, duplicate is different/less powerful ( up to you, to simulate being to different people) Multiform this is your "gestalt form",trigger on (recombining with your duplicate), trigger off ( a time limit perhaps? because you cant maintain the form for too long or something) then, switching back to your regular form triggers the duplicate This is a basic idea of what i thought of, sorry i don't have the math all figured out.