[quote=@NarcissisticPotato]
Raijin are these different people? I thought they were kind of like ghosts that only Jackson could see?

Anyways, is everyone doing ok? Anyone lacking in things to do?
[/quote]

They are a mix of alternate personalities and voices in his head. They can be created either by being placed in a stressful situation, which is how Mu was born, or by having a strong desire to change something about ones self, as Kuro was born out of Jackson's wish to be more out going, unfortunately he wasn't really specific and thus made something that is Jackson's opposite in most ways.

Basically, different minds inside of one body.