Accidental Creation, Question about creating what I belive to be are 'thought forms' Options

Since I was about 12 I would create characters as I like to call them. At first they were on paper and only there ... then they seemed to widdle their way into ... well, me. They talk and they seem to take on certain purposes within myself, almost like a strange possession or like I'm using their attributes. I know this sounds like I'm crazy, but they seem to have developed a mind of their own .... I know longer know if they even originated from me because they're so different from my initial intentions..... They even have their own .. voices now. There are now more than five of them. It's not like they're harmful, but I want to know what they are and what exactly I did to make them or where they came from if they aren't from me.

^if this a multiple personality disorder some personalities very well may be unaware of others. And some may be aware while some others were not