Your Brain don't holds your memory it is just a nature device that receives and sends data to the core.

The Dark souls already knew it and disconnect them self from nature of fear or doubt, and they seek now how to trap souls of course because they can replicate their bodys and live forever without reincarnation. But the problem with that is that you wont get any upgrade anymore no one that will teach you this is why they are here to steal again something they miss.

But don't forget as how much they try to do evil its just on the physical plane and as we are immortal after death you can reborn "IF" you wish to do it.

The balance of the universe is very important and i don't think that that one that believe in the light and growth will always help the poor.