I don't know man souls are nebulous. Some need them to live, some can live without them (with difficulty). They can come in many colors and are reflections of who the people they reside in are truly like at their core.
Interneters have their own version of souls called "coreware". It is the code that tells them who to be and how to function, and can be changed to alter their very beings and who they are as people. Hatusne Mikaiju has used this vulnerable aspect to make her subjects loyal to her.
Pieces of the void have souls that are always the size of their forms, growing and shrinking along with how much matter comprises them.