For me no new alters were created. Sometimes though I had alters that I thought were new only to find out they were there the whole time they were just at a deeper "level" than some of the others. my system of alters worked kind of like orbits around the earth there were many alters on different orbiting levels circling me to protect and take care of me. As we worked in therapy and took care of things on one orbit, the alters on another orbiting level came into my awareness. My therapist and I took things one level, one alter at a time. Being here Ive read some posts where some people have said its like peeling an onion. you peel through each layer and with each layer comes new things and sometimes new alters you didn't know was there that you have to deal with. I like the onion idea too. makes sense to me.