Duplication for Speedsters

[TGLS]

Originally Posted by BaHalus

I am making a super-speedster like the Flash.
I think that, among other more obvious advantages, Duplication is also a good fit, as sometimes Flash acts as if he is in several places at the same time

I'm not sure if it is a good fit. For example, if duplicate A got on a plane, and duplicate B stayed at home, how is the same individual travelling back and fourth between these two points?